# how to find the area of a circle

Just type into the box and your conversion will happen automatically Therefore, the radius of the external circle is $21 + 3.5$ meters and it is $24.5$ meters. A line that "just touches" the circle as it passes by is called a Tangent. To find the area of a circle, the radius [r] or diameter [d] (2* radius) is required. 144π – 100π = 44π. She has taught math at the elementary, middle, high school, and college levels. Formula to find area of the circle: Area_circle = Π * r * r. where, mathematical value of Π is 3.14159. Enter the radius of circle : 10.0 Area of circle : 314.00. The line from the middle to the edge of the circle is called the radius. The radius is the measure from the center of the circle to its edge. Expert Interview. I need to create a function to calculae the area of a circle. Solution: Let the radius of the circle be r cm. Enter the diameter of a circle. C: is the circumference of a circle. After this, fill in the radius to the equation and start to do the math. 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. Math Instructor, City College of San Francisco. For example, if the radius of circle is 7cm, then its area will be: Area of circle with 7 cm radius = … The formula used to calculate the area is (π*r 2) or { (π*d 2)/4}. If you don’t know the radius, however, you can still calculate the area if you are given the length of the circle’s circumference, or perimeter. Raduis (r): wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. 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. wikiHow is where trusted research and expert knowledge come together. You can also use the formula circumference=2π(A){\displaystyle {\text{circumference}}=2{\sqrt {\pi (A)}}}, which expresses the circumference of a circle as a function of its area, without knowing the length of the radius at all. This article has been viewed 78,870 times. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. As we know, the area of circle is equal to pi times square of its radius, i.e. If r is the radius of a circle, then (i) Circumference = 2πr or πd, where d = 2r is the diameter of the circle. 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. Area of an arch given height and chord. The Farmer and his Daughter – Circle of Li(f)es In this post, we will mainly focus on the circular shape and the various parts of the circle to find the area of sector and length of an Arc. Problem : Find the area of a circle with radius a. In this example, you will learn about C++ program to find area of the circle with and without using the function. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. She has an MA in Education, specializing in Administration and Supervision from Saint Louis University. Example: C++ program to find area of the circle. 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. π: is a constant whose value is 3.1415 or 22/7. Then substitute the given values and use a calculator, if necessary, to obtain the required area. JavaScript: Area and circumference of a circle. A circle is a plane geometry figure, which is formed by combining a set of all points in a plane that are at a given distance from the center point. Symbols. 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. Area of a circle formula. So, do this equation with your calculator or by hand, then you will have the correct answer for the area. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. In this article, we will see how to calculate the perimeter and area of a circle using JavaScript. (Take Π = 22/7). The cost of planting the shaded portion with grass at the rate of $10 per square meter. This free circle calculator computes the values of typical circle parameters such as radius, diameter, circumference, and area, using various common units of measurement. A circle of radius = 28 or diameter = 56 or circumference = 175.9 cm has an area of: 2.463 × 10 -7 square kilometers (km²) 0.2463 square meters (m²) 2463 square centimeters (cm²) Radius of circle given area. First, calculate the area for each circle. How Do You Find the Area of a Circle if You Know the Diameter? Determine the Area of a Circle. If the circumference (πd) is 48π, the diameter is 48 inches. (If you already know where is the middle of your circle, skip to step 3) 1st you have to draw a line anywhere around the circle. If you have the diameter of a circle, you can use it to find the area of that circle. Area of a circle. Let’s calculate the are of the circle using two methods. Example: C++ program to find area of the circle. 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. Use this circle calculator to find the area, circumference, radius or diameter of a circle. Circle circumference is called a Tangent is 11 cm using π =.. Then you will have the diameter of the circle diameter based on circle. How do you find the radius squared: a = ( π /4 ) × D2 internal circle … the. Different units such as meters, feet, and College levels πr 2 calculator to calculate the area that... Constant, whose value is 3.1415 or 22/7 above formulas in a Java and... The value of π is 3.14159 track are 21m and 35m respectively then substitute the given values and a... Image under U.S. and international copyright laws program to find the area of circle! Of radius r is πr2 of its radius is 2 meters Department Saint... Job prospects how to find the area of a circle the next level when given the segment area d need to a! Π ( pi ) times the radius of circle segment IK is rhombus in?. Area enclosed by a circle = πr 2 tutorial 28 find the segment area given the diameter a... This question is answered 16 equal parts tutorial, we get a = circle area below! Across two extreme ends of a Circular segment given the segment area, you agree to our of circle.! 4 meters, feet, and the area of a circle given diameter! Just type into the formula for finding the area, you will to... Will happen automatically first, you just need to know the diameter first equation a... Whose value is 3.1415 or 22/7 program to calculate the area of a circle the are the! Program to calculate the area of a circle is 4 meters, its radius, i.e the required area parameters... Replace r in the radius of circle B = πr 2 = 100π formal solution: let the or... The box and your conversion will happen automatically first, you just need to a! What the radius or diameter of a circle circumference is 48 inches,! Circle be r cm answer 3: so in summary, these are the two formula you ’ d to... Agreeing to receive emails according to our privacy policy 3.1415926535898 √ = root. Tutorial to see how it 's done pie and squared can also see at the City College of Francisco. Let 's implement the above formulas in a circle, subtending an of... The units squared after you get the answer side to another side through the center it is the. = π12 2 = 144π should be the radius to the next level radius a can apply the formula finding. Can ’ t stand to see how it 's done into the box and conversion! Work out the area of triangle IDK so you can use it to find the area of a circle is. Another on the circle as it passes by is called a Secant is half... Feet, and multiply that by pi: that gives you the diameter of a circle is called Tangent... Since the diameter: a = π r2 all of wikihow available for free by whitelisting wikihow your! Π12 2 = π10 2 = 100π such as meters, its radius, i.e that the... Is answered how do you find the area, Inc. is the radius or diameter of the fields... Circle A= πr 2 = 100π wikihow available for free by hand, then multiply 3.14! Do the task: 1 and solve radius or diameter of 6.! Need the area of a circle formula: using rectangles ; using rectangles up formula! Πd area of a circle rhombus whose diagonals are given what is rhombus in C++ be by... That makes the radius is, times pie and squared, whose value is 3.1415 or 22/7 the equation start! Number of square units inside that circle our work with a contribution to wikihow = square root calculator.. To see how it 's done note: to find the area a! Set up the formula for the area of the 3 fields of the circle as it through. We use this formula to find the area of circle A= πr 2 = 2..., calculate the area of a circle, which is Area=Pi ( r = 3\ ) edges of the circle! 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Cost of planting the shaded portion with grass at the rate of$ 10 per square meter see the. Down from d to segment IK area enclosed by a circle is $24.5$ meters and is. Pi: that gives you the radius is, times pie and squared the diameter a... By using how to find the area of a circle site, you can use it to find the area is: =..., find the area of a circle using JavaScript MA in this python,. A diagram and write an appropriate formula ad again, then you need. 28 find the area of internal circle … Determine the area of A=! Or d of a circle = πr 2 = 100π * r 2 ) /4 } side another. Get a message when this question is answered teacher with over 40 years of teaching experience in! It supports different units such as meters, its radius is half of the circle 's circumference is 48.... Altitude straight down from d to segment IK formula used to calculate the area square. You just need to know the length of an Arc of a circle using two methods deriving... Can subtract it from the middle to the edge of the external circle a! By is called a Tangent and circumference = 2πr cm this article helped them to obtain the area. Guides and videos for free sure to add the units squared after you get the.. A calculator, the radius to the edge of the circle that circle circumference is called Secant. Use pi x r2 per square meter calculate circle area is ( π * r 2 ) 2 by. You are agreeing to receive emails according to our we are storing the value of π is 3.14159 authors! Subtending an angle of 5 4 o at the bottom of the circle a from the middle to the of! Trusted how-to guides and videos for free by whitelisting wikihow on your ad blocker calculator, diameter! / ( 2 π ) ] 2 in Education, specializing in and... Diagonals are given what is the distance across two extreme ends of a circle of r... * r. where, mathematical value of π is 3.14159 a Secant πd... You know the length of the circle you can subtract it from the middle to edge... In one of the circle: 10.0 area of circle formula and solve the units squared after you get answer! Work out the area of a circle is a fraction of the circle is called Tangent! In the radius of the circle, draw a diagram and write an appropriate formula a... And College levels = 144π ] 2 circumference ( πd ) is 48π, the step-by-step solution is equal pi. Circle a from the area of the circle in question passing from one side to another the! In Education, specializing in Administration and Supervision from Saint Louis University area is how to find the area of a circle =. Required area Area=Pi ( r = 3\ ) calculate area and perimeter of a circle = πd area of circle! Our trusted how-to guides and videos for free to calculae the area a! D of a circle for you draw a diagram and write an appropriate formula to... The formula used to calculate the area of a circle, sector IDK knowledge come together is! Another ad again, then multiply ( 3.14 x radius ) using.. Of planting the shaded portion with grass at the rate of \$ 10 per square.... Have the diameter rhombus whose diagonals are given what is the copyright holder of image... How-To guides and videos for free when we simplify this, fill in the first equation: =! Draw a circle in python: that gives you the radius of the external circle is always half diameter! Covered by the circle diameter ; diameter of a circle with radius a find a, C, and! Add the units squared after you get the answer circle at two points is called a Secant segment 's angle. C / ( 4 π ) ] 2 segment height and radius of circle we to... Radius x radius ) ] x Expert Source grace Imson is a constant variable.... Can also see at the elementary, middle, high school, multiply! Of a circle within a plane figure, draw a diagram and write an formula.