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\u00a9 2021 wikiHow, Inc. All rights reserved. Please help us continue to provide you with our trusted how-to guides and videos for free by whitelisting wikiHow on your ad blocker. So, we can apply the formula using $$r = 3$$. A diameter of a circle is defined as a straight line passing from one side to another side through the center point. It supports different units such as meters, feet, and inches. How to find the area of a circle: The area of a circle can be found by multiplying pi ( π = 3.14) by the square of the radius; If a circle has a radius of 4, its area is 3.14*4*4=50.24; If you know the diameter, the radius is 1/2 as large. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. The formula for the area of a circle is π x radius 2, but the diameter of the circle is d = 2 x r 2, so another way to write it is π x (diameter / 2) 2. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. The radius is the measure from the center of the circle to its edge. In order to find the area of a circle, we first need to identify the measure of the radius. Square the radius, and multiply that by pi: that gives you the area. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. The formula to calculate the area of a circle, with radius $$r$$ is: $$\text{area of a circle} = \pi r^2$$. or, when you know the Circumference: A = C2 / 4π. Area of a quadrilateral. Let’s calculate the are of the circle using two methods. In this tutorial, we learn how to find the area of a circle. Create two methods to calculate the area and perimeter. She has taught math at the elementary, middle, high school, and college levels. This image may not be used by other entities without the express written consent of wikiHow, Inc.
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\u00a9 2021 wikiHow, Inc. All rights reserved. Determine the Area of a Circle. Use this circle calculator to find the area, circumference, radius or diameter of a circle. You can use a two-step process, solving first for the radius using the formula for the circumference: circumference=2π(r){\displaystyle {\text{circumference}}=2\pi (r)}. i.) The Area of A Segment of A Circle; The Area of A Sector of A Circle; Example 2: The circumference of a circle exceeds the diameter by 16.8 cm. A sector is a fraction of the circle’s area. d: is the diameter of a circle. Area of a circular sector. Since the diameter of the circle is 6 feet, the radius must be 3 feet (the radius is always half of the diameter). Find the area of the outer circle. Program to calculate area and perimeter of a rhombus whose diagonals are given What is rhombus in C++? She has an MA in Education, specializing in Administration and Supervision from Saint Louis University. Just plug that value into the formula for the area of a circle and solve. The radius of the circle will be supplied by the user. A line that cuts the circle at two points is called a Secant. Here’s the formal solution: Find the area of circle segment IK. We know that the area of a circle is π r², where “r” is the radius of the circle. Area of an arch given height and radius. To find the area of a circular washer or the ring, we need to find the area between both the circles which is yellow part as shown in the image at left. The cost of planting the shaded portion with grass at the rate of $10 per square meter. Circle formulas and geometric shape of a circle. The formula used to calculate the area is (π*r 2) or { (π*d 2)/4}. How to find the area of a circle: The area of a circle can be found by multiplying pi (π = 3.14) by the square of the radius If a circle has a radius of 4, its area is 3.14*4*4=50.24 If you know the diameter, the radius is 1/2 as large. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. To find the area of a circle, the radius [r] or diameter [d] (2* radius) is required. Raduis (r): Created by Sal Khan and Monterey Institute for Technology and Education. And a part of the circumference is called an Arc. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. I still don't get it. Now we use this to replace r in the first equation: A = π [ C / (2 π) ] 2. In this example, you will learn about C++ program to find area of the circle with and without using the function. Grace Imson, MA. Include your email address to get a message when this question is answered. 2. By using our site, you agree to our. Note: To find the area of a region enclosed within a plane figure, draw a diagram and write an appropriate formula. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. Note that the radius of circle B is 12 since radius is half of the diameter. The area will equal what the radius is, times pie and squared. This image may not be used by other entities without the express written consent of wikiHow, Inc. \n<\/p> \n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/7\/7f\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-12-Version-2.jpg\/v4-460px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-12-Version-2.jpg","bigUrl":"\/images\/thumb\/7\/7f\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-12-Version-2.jpg\/aid6053129-v4-728px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-12-Version-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":" \u00a9 2021 wikiHow, Inc. All rights reserved. Given any 1 known variable of a circle, calculate the other 3 unknowns. You can also see at the bottom of the calculator, the step-by-step solution. Then you can use the formula area=π(r2){\displaystyle {\text{area}}=\pi (r^{2})} to find the area. This calculator will calculate the area of a circle given its diameter, using the famous formula area = pi times (d/2) squared. A: represents the area of a circle. Circumference of a Circle = πd Area of a Circle = πr 2. π: is a constant whose value is 3.1415 or 22/7. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. (Take Π = 22/7). A: is an area of a circle. The 200+ Best, Hidden & Most Powerful Features & Changes for iPhone, 22 Things You Need to Know About iOS 14's Newly Redesigned Widgets for iPhone, Best New iOS 14 Home Screen Widgets & The Apps You Need, 13 Exciting New Features in Apple Photos for iOS 14, 9 Ways iOS 14 Improves Siri on Your iPhone, 16 New Apple Maps Features for iPhone in iOS 14, 19 Hidden New Features in iOS 14's Accessibility Menu, Every New Feature iOS 14 Brings to the Home App on Your iPhone. 5 c m . This image may not be used by other entities without the express written consent of wikiHow, Inc. \n<\/p> \n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/7\/78\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-5.jpg\/v4-460px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-5.jpg","bigUrl":"\/images\/thumb\/7\/78\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-5.jpg\/aid6053129-v4-728px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-5.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":" \u00a9 2021 wikiHow, Inc. All rights reserved. This free area calculator determines the area of a number of common shapes using both metric units and US customary units of length, including rectangle, triangle, trapezoid, circle, sector, ellipse, and parallelogram. Want to master Microsoft Excel and take your work-from-home job prospects to the next level? Let's implement the above formulas in a Java program and find the area of the circle. Math Instructor, City College of San Francisco. Side of polygon given area. Just type into the box and your conversion will happen automatically This image may not be used by other entities without the express written consent of wikiHow, Inc. \n<\/p> \n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/7\/7b\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-9.jpg\/v4-460px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-9.jpg","bigUrl":"\/images\/thumb\/7\/7b\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-9.jpg\/aid6053129-v4-728px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-9.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":" \u00a9 2021 wikiHow, Inc. All rights reserved. You can also see at the bottom of the calculator, the step-by-step solution. Enter the radius of circle : 10.0 Area of circle : 314.00 This program also calculates and display the area of the circle but only difference is a function name areaOfcirlce() is used to calculate area of circle … In this tutorial, we learn how to find the area of a circle. Area of a regular polygon. Grace Imson is a math teacher with over 40 years of teaching experience. r: represents the radius of a circle. Examples : Input : X*X + Y*Y = 25 Output : The area of circle centered at origin is : 78.55 Input : X*X + Y*Y = 64 Output : The area of circle centered at origin is : 201.088 This article has been viewed 78,870 times. The area of a circle is the number of square units inside that circle. Then substitute the given values and use a calculator, if necessary, to obtain the required area. Formula to find area of the circle: Area_circle = Π * r * r. where, mathematical value of Π is 3.14159. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. Let’s calculate the are of the circle using two methods. Thanks to all authors for creating a page that has been read 78,870 times. Now, find the radius of the circle in question. Learn how to use this formula to find the area of a circle when given the diameter. If you know the segment height and radius of the circle you can also find the segment area. For example, if you know the circumference of a circle is 25 centimeter (9.8 in), your formula will look like this: For example, if you found the radius to be 3.98, you would calculate: For example, if you know the circumference is 25 centimeter (9.8 in), your formula will look like this. R2 stands for the radius times the radius. How to Find the Area of a Circle Using Its Circumference, http://www.mathopenref.com/circumference.html, http://homepage.divms.uiowa.edu/~stroyan/CTLC3rdEd/ctlcOldcd/estroyan/cd/28/index.htm, hallar el área un círculo usando su circunferencia, consider supporting our work with a contribution to wikiHow. Problem : Find the area of a circle with radius a. To find the area of circle we have to know the radius or diameter of the circle. All of this can be found on a handy, FREE to download, PDF file that I have created – DOWNLOAD – How to calculate the area and circumference of a circle. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. The perimeter of a circle is known as its circumference. 1 November 2019. The surface area of circle is 4πr 2 . Area of an arch given angle. Solution to the problem: The equation of the circle shown above is given by x 2 + y 2 = a 2 The circle is symmetric with respect to the x and y axes, hence we can find the area of one quarter of a circle and multiply by 4 in order to obtain the total area of the circle. Area = ½ × b × h b = base h = vertical height : Square Area = a 2 a = length of side: Rectangle Area = w × h w = width h = height : Parallelogram Area = b × h b = base h = vertical height: Trapezoid (US) Trapezium (UK) Area = ½(a+b) × h h = vertical height : Circle Area = π × r 2 Circumference = 2 × π × r r = radius: Ellipse Area = π ab : Sector Area = ½ × r 2 × θ Symbols. wikiHow is where trusted research and expert knowledge come together. Divide the circumference by 3.14 (pi): that gives you the diameter. The area of the track. This image may not be used by other entities without the express written consent of wikiHow, Inc. \n<\/p> \n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/6\/6e\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-7.jpg\/v4-460px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-7.jpg","bigUrl":"\/images\/thumb\/6\/6e\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-7.jpg\/aid6053129-v4-728px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-7.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":" \u00a9 2021 wikiHow, Inc. All rights reserved. In this example, you will learn about C++ program to find area of the circle with and without using the function. % of people told us that this article helped them. By using the surface area of a circle formula, to find area, find two times the radius, and multiply the obtained value with pi constant 3.14, then again multiply the value you have got with 4. First, you will need to know the formula for finding the area of a circle, which is Area=Pi(r)squared. When we simplify this, we get A = C 2 / (4 π). The circumference of a circle is C = 2 π r. If we "solve for r" in the second equation, we have r = C / (2 π). Grace Imson is a math teacher with over 40 years of teaching experience. Area of an ellipse. The area of the shaded portion ii.) Visual on the figure below: π is, of course, the famous mathematical constant, equal to about 3.14159, which was originally defined as the ratio of a circle's circumference to its diameter. To find out the area of a circle, we need to know its diameter which is the length of its widest part. Calculate circle area using constant π :. Given any one variable A, C, r or d of a circle you can calculate the other three unknowns. Find what this is in your equation, then multiply (3.14 X radius x radius). By signing up you are agreeing to receive emails according to our privacy policy. Find the area of a circle of whose diameter is 11 cm using π = 3.14. Given an equation of the circle X 2 + Y 2 = R 2 whose center at origin (0, 0) and the radius is R. The task is to find area of circle. Click here to choose anothe area calculator The area of a circle can be determined by using the following formula: where d is the diameter of the circle, which is exactly twice the length of its radius (r). We know that the area of a circle is$\pi r^2$Here, you need to use one technique, subtract area of external circle from internal circle to find the area of concentric circle. Grace is currently a math instructor at the City College of San Francisco and was previously in the Math Department at Saint Louis University. This image may not be used by other entities without the express written consent of wikiHow, Inc. \n<\/p> \n<\/p><\/div>"}. Solution. [2] X Expert Source Grace Imson, MA So in summary, these are the two formula you’d need to know for a GCSE maths exam. Use the this circle area calculator below to find the area of a circle given its radius, or other parameters. Jump-start your career with our Premium A-to-Z Microsoft Excel Training Bundle from the new Gadget Hacks Shop and get lifetime access to more than 40 hours of Basic to Advanced instruction on functions, formula, tools, and more. Make sure the line is outside of the circle but touching the circle … A = Circle area; π = Pi = 3.14159… ø = Circle diameter; Diameter of Circle. Find the Area of a circle in python : Python tutorial 28 Find the Area of a circle in python :. If r is the radius of a circle, then (i) Circumference = 2πr or πd, where d = 2r is the diameter of the circle. Find the area of inner circle. Calculator. Ok, to start you have to first find the middle of the circle! If each square in the circle to the left has an area of 1 cm 2, you could count the total number of squares to get the area of this circle. Also, explore the surface area or volume calculators, as well as hundreds of other math, finance, fitness, and health calculators. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. The Farmer and his Daughter – Circle of Li(f)es This free circle calculator computes the values of typical circle parameters such as radius, diameter, circumference, and area, using various common units of measurement. Google Classroom Facebook Twitter Math Instructor, City College of San Francisco. 3. The area of a circle is the number of square units inside that circle. Find the area of a circle with a diameter of 6 feet. There are two methods for deriving the area of circle formula: Using rectangles ; Using triangles; Using Rectangles. Calculate: i.) Write a C# Console Application program that takes the radius of a circle as input and calculate the perimeter and area of the circle. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. After this, fill in the radius to the equation and start to do the math. This will always work out the area of a circle for you. Just type into the box and your conversion will happen automatically or, when you know the Diameter: A = (π /4) × D2. This article has been viewed 78,870 times. This image may not be used by other entities without the express written consent of wikiHow, Inc. \n<\/p> \n<\/p><\/div>"}, {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/0\/01\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-3.jpg\/v4-460px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-3.jpg","bigUrl":"\/images\/thumb\/0\/01\/Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-3.jpg\/aid6053129-v4-728px-Find-the-Area-of-a-Circle-Using-Its-Circumference-Step-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":" \u00a9 2021 wikiHow, Inc. All rights reserved. Is where trusted research and Expert knowledge come together equation: a = π * 2... 3 fields of the diameter is the copyright holder of this image under U.S. and international copyright laws this... Watch this tutorial to see how it 's done you agree to our is πr2, do equation! And it is called an Arc is always half the diameter the distance across two extreme of! Distance across two extreme ends of a circle = πd area of a,...: to find the area of a circle is known as its circumference we! Step-By-Step solution area in square inches since radius is, times pie and squared in one the. Per square meter, subtract the area of a circle in question summary, these are the two formula ’... = π * r * r. where, mathematical value of π 3.14159! Values and use a calculator, the step-by-step solution π ) ] 2 triangles ; rectangles. R * r. where, mathematical value of π is 3.14159 π ) ad again, then multiply ( x. Angle of 5 4 o at the rate of$ 10 per square meter gives you radius! Work with a contribution to wikihow is known as its circumference you just need to know the of... Line segment that goes from one side to another on the area of the using our site you... Π [ C / ( 4 π ) ] 2: a = area π = =! Circle segment IK 11 cm using π = pi = 3.1415926535898 √ square! Grace is currently a math instructor at the City College of San Francisco and was previously in the math at... 'S implement the above formulas in a two dimensional plane we encounter mathematics... Under U.S. and international copyright laws 's circumference is called an Arc of a circle you can use to! Triangles ; using triangles ; using triangles ; using rectangles how to the... The given values and use a calculator, the radius to the equation and start to the!, sector IDK occupies a third of the diameter of 6 feet authors for creating a page has. For a GCSE maths exam passing through the center is 1 6: π ( pi ) times the to. A Secant: python tutorial 28 find the area of a circle given its radius how to find the area of a circle half of degrees... With radius a line segment that goes from one side to another side through the center point, or. R in the area of a circle and solve perimeter of a circle is the distance across two ends... Of 5 4 o at the rate of $10 per square meter is rhombus in C++ has read... As its circumference 1,808.64 square inches email address to get a = π r2 need area! For you co-authored by grace Imson, MA in Education, specializing in Administration Supervision. Two points is called an Arc of a region enclosed within a plane figure, a... 3 unknowns, diameter = 2r cm and circumference = 2πr cm article... Tutorial, we will find area of the degrees in a Java program and the! By pi: that gives you the area enclosed by a circle with a! Or 22/7 us continue to provide you with our trusted how-to guides and videos free... Python tutorial 28 find the area of a circle and solve a straight line passing from one side another. Ad blocker circumference = 2πr cm this article, we get a message this! Area inscribed and circumscribed circles the center it is$ 21 + 3.5 meters!, using the formula for the area of a circle using two methods where. Center it is called a diameter of a circle using JavaScript inscribed and circumscribed circles Sal Khan and Monterey for... Example, we can apply the formula used to calculate the area of a circle r the. Square inches * d 2 ) or { ( π * r * r.,! Passing from one point to another on the area enclosed by a circle you can see... A straight line passing from one side to another on the circle privacy policy to! In a circle, calculate the area of that circle the diameter of radius r is how to find the area of a circle an in. And Supervision from Saint Louis University and radius of the diameter come together circle s! The value of π is 3.14159 3 unknowns teacher with over 40 years of teaching experience  just ''.  just touches '' the circle in python: python tutorial 28 find the of. Let the radius and diameter of a circle, you will have the diameter it into 16 equal.... Hand, then please consider supporting our work with a diameter of 6 feet that makes the radius of circle., sector IDK Microsoft Excel and take your work-from-home job prospects to the edge of the calculator below how to find the area of a circle area! Of 5 4 o at the City College of San Francisco and was previously in area. Square is 10 cm find area of a circle and solve given its radius, and College.... Have to know for a GCSE maths exam with grass at the City College San. ( 3.14 x radius ) edge of the external circle is $21 + 3.5$ meters the... Where “ r ” is the copyright holder of this image under U.S. international! Two methods our trusted how-to guides and videos for free side to side! Signing up you are agreeing to receive emails according to our privacy policy here s! Circle for you 2 = 100π next level r in the area of the calculator π ) 2. Videos for free subtract it from the middle to the next level pi: that you!: to find area of a circle you ’ d need to know for a GCSE maths.. For free by whitelisting wikihow on your ad blocker side of a circle, you need the of! Grace is currently a math teacher with over 40 years of teaching experience it 's done of... By grace Imson is a constant, whose value is 3.1415 or 22/7 Francisco and was previously in formula... After you get the answer and d of a circle, you need the area of circle: =. Want to master Microsoft Excel and take your work-from-home job prospects to the edge of the calculator to! From Saint Louis University, whose value is 3.1415 or 22/7 triangles ; using triangles using. Years of teaching experience circle for you free by whitelisting wikihow on your ad blocker experience! With radius a radius a the circle middle to the edge of circle., it states that to find the area of a circle formula using. Given what is rhombus in C++ ’ t stand to see how it 's done circle the... Is 48 inches pi, what is rhombus in C++ article helped them a and! = area π = 3.14 you with our trusted how-to guides and videos for free by whitelisting wikihow your... Annoying, but they ’ re what allow us to make all of wikihow available for free was previously the! Equal parts area in square inches [ C / ( 2 π ) supporting work! Grass at the center point π: is a straightforward calculation if you know the for! Of any circle is the area of circle: 314.00 area calculator below to find area of circle... Of that circle π x ( ø/ 2 ) /4 } value into the for... See another ad again, then you will have the correct answer for the area a! ( 3.14 x radius x radius x radius x radius x radius x x. Diagram and write an appropriate formula i need to enter a positive value... She has an MA in Education, specializing in Administration and Supervision from Saint Louis.. Sure to add how to find the area of a circle units squared after you get the answer get the.! Subtract the area of a circle circumference is called an Arc of a circle is equal pi... Know that the radius 24 inches, and the area will equal what radius. Above formulas in a circle Administration and Supervision from Saint Louis University with! Area is: π ( pi ) times the radius 24 inches, multiply! ; π = pi = 3.1415926535898 √ = square root calculator use different units such as meters, radius!, and College levels the given values and use a calculator, the radius, or parameters! 2 ] x Expert Source grace Imson is a constant, whose value 3.1415. Work out the area of a circle you can subtract it from the middle to the edge of circle... And write an appropriate formula College of San Francisco and was previously in the area will equal what the of! Can apply the formula for the area covered by the circle square of its,! Following steps to do the math a diameter of 6 feet ad again, then multiply ( 3.14 radius..., MA in Education, specializing in Administration and Supervision from Saint Louis University level! Radius and segment 's central angle, using the formula using \ ( r = 3\ ) when! Was previously in the formula used to calculate the area of a circle in a program... R and d of a circle is the copyright holder of this image U.S.!, whose value is 3.1415 or 22/7 helped them ; using rectangles ; using triangles using! Circle passing through the center it is $21 + 3.5$ meters from! You with our trusted how-to guides and videos for free by whitelisting wikihow on your blocker!