# how to find the area of a circle

I'm also glad I could download the images. Required fields are marked *. 08, Jan 20. Next, multiply the squared radius by pi to get the area. Area of the circle that has a square and a circle inscribed in it. Here’s a handy diagram, recapping the component parts of a circle: So in summary, these are the two formula you’d need to know for a GCSE maths exam. A perimeter of closed figures is defined as the length of its boundary. Formula to find area of the circle: Area_circle = Π * r * r. where, mathematical value of Π is 3.14159. We know that the circumference/ perimeter of the circle is 2πr cm. It can be determined easily using a formula, A =, . It is given by; Here, the value of pi, π = 22/7 or 3.14 and r is the radius. ", "It works well, I'll be using this again.". Your email address will not be published. The area is a quantity that represents the extent of the figure in two dimensions. But, one common question arises among most of the people is “does a circle have volume?”. In this example we will calculate area and circumference of the circle according to given radius. Calculator. Since the formula for the area of a circle squares the radius, the area of the larger circle is always 4 (or 2 2) times the smaller circle. After cutting the circle along the indicated line in fig. The user provides an option and the switch statement executes the corresponding case. A common problem in geometry class is to have you calculate the area of a circle based on provided information. Suppose, if you have the plot to fence it, then the area formula will help you to check how much fencing is required. % of people told us that this article helped them. This circumference is the length of the boundary of the circle. metres). If you know the segment height and radius of the circle you can also find the segment area. The mathematical formula for calculating the perimeter and area of the circle is given below: Area of circle = π * r * r Perimeter of circle = 2 * π * r Both formulae require the value of PI. The circumference of a circle is the linear distance around its edge. C = 2πr Moreover, i f the radius of Circle is 5.0, then the Area of Circle will be 78.525. The surface area of the circle = A =  π x r2. Hence, the concept of area as well as the perimeter is introduced in Maths, to figure out such scenarios. For this example, assume that you have been told or have measured that the circumference of a circle (or circular object) is 42 cm. When the length of the radius or diameter or even the circumference of the circle is already given, then we can use the surface formula to find out the surface area. 4 and spreading the lines, the result will be a triangle. ", "It really helped. ", "I only had a slim clue on how to calculate the area of a circle, and this helped me fully understand. If the number of sectors cut from the circle is increased, the parallelogram will eventually look like a rectangle with length equal to πr and breadth equal to r. The area of a rectangle (A) will also be the area of a circle. Since the sectors have equal area, each sector will have equal arc length. To find the segment area, you need the area of triangle IDK so you can subtract it from the area of sector IDK. Use the this circle area calculator below to find the area of a circle given its radius, or other parameters. It can be difficult to measure to the exact center of a circle, unless the center is already marked for you on a circle drawn on paper. You can find the area of a circle using the radius, the diameter, or the circumference. Whenever I do not know something, I always come to this website! Think about it: You are doubling a number (which means ×2) and then squaring this (ie squaring 2) -- which leads to a new area that is four times the smaller one. Formula for area of a circle. ", "I was able to get a more comprehensive note from here. In an easy way we can say, it is just the double of the radius of the circle and is represented by’d’ or ‘D’. The circumference of a circle is the perimeter of the circle, and the interior of the circle is called a disk. A circle is nothing but the 2-D representation of a sphere. Answer: The formula of arc length is L = r × Θ. Program to calculate area of inner circle which passes through center of outer circle and touches its circumference. (If you're asking how to convert from square inches to square feet, divide the number of square inches by 144 to get square feet.). Given, the circumference of a circle = 30cm, We know, from the formula of circumference, C =2πr. If you really can’t stand to see another ad again, then please consider supporting our work with a contribution to wikiHow. The formula: Area of a Circle = π x (Diameter/2)^2 π = 3.142 Answer = (π x (Diameter/2)^2) square area Here, we can calculate the area of a circle using a diameter or using a radius. The formula is simple and only needs the radius of the circle to find its area. This article has been viewed 5,217,159 times. For example: If d= 23cm, C= 3.14 x 23cm, so C= 72.22cm. metre). You can also see at the bottom of the calculator, the step-by-step solution. Basically, a circle is a closed curve with its outer line equidistant from center. ", "This article will help me pass the math exams for getting a score in school. The diameter of the circle is the line which divides the circle into two equal parts. metres) with the area’s applicable circle rate (in Rs./sq. Area of a circle is the region occupied by the circle in a two-dimensional plane. 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. 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. The formula used to calculate circle area is: A = π x (ø/ 2) 2. You can find diameter of a circle by multiplying the radius of a circle by two: There are 16 references cited in this article, which can be found at the bottom of the page. Program to calculate area of an Circle inscribed in a Square. The radius will generally be provided to you. The radius is the straight-line distance from the centre of a circle to the edge of the circle. If you want to find the area of a sector from a circle, keep reading the article! To find the area of a circle, the radius [r] or diameter [d] (2* radius) is required. Let us solve some problems based on these formulas to understand the concept of area and perimeter in a better way. How do I find the total area of five circles joined together? C program to find the area of a circle: C programming code to calculate the area of a circle. If we know the diameter or circumference, we find the radius from it. ", "It is my exam math exam and i forgot to ask my teacher about how to find a circle's area, this helped me so much! When it comes to circles, the perimeter is given in a different name. Since a circle is a, Frequently Asked Questions Using Area of Circle Formula. The unit of area is the square unit, such as m2, cm2, etc. π x r2. Furthermore, find the area with the diameter, simply divide the diameter by 2, moreover, put the value in the radius formula, and solve it as before. 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. Your email address will not be published. 3. This article was co-authored by Grace Imson, MA. As we know, the area of circle is equal to pi times square of its radius, i.e. The area of a circle is the area covered by the circle in a two dimensional plane. This article was co-authored by Grace Imson, MA. How do I convert inches to feet when finding the area of a circle? find myself struggling. How? The area of a circle is pi times the radius squared (A = π r²). ", "Math has never been my strong point. Therefore, the area of the circle is 113.04 inches squared. Last Updated: December 27, 2020 The red coloured sectors will contribute to half of the circumference, and blue coloured sectors will contribute to the other half. In the above figure, we can see a circle, where radius r from the centre ‘o’ to the boundary of the circle. To find the area using the circumference, or the distance around the circle, use the formula area = c^2/4π, where c is the circumference. Therefore, the area of the circle is 314.16 inches squared. In the following Java program, we have used a Java switch case because we have used three scenarios to find the area of the circle. Therefore, here we can find the value of radius, Most basically, you will need to find the areas of each circle separately, and then add them up. However, you need to change the formula so that you square the 'd' otherwise your answer will be wrong. For the given example with a radius of 6 cm, the area is calculated as: For the sample circle with a radius of 6 cm, the area will be either 36. ", "Very good and detailed, helps me understand what school doesn't teach and finish a subject. For example: if the radius of Circle is 3.0, then the Area of Circle will be 28.26. Measure the outside circumference of the pipe, or the outside diameter using something like calipers. Therefore, the area of the circle is 140.4 square inches. Math Instructor, City College of San Francisco. Using Radius to Find Area Identify the radius of a circle. Multiply minimum construction cost (in Rs./sq. Area of a circle program in C Radius r: Central angle a (degrees) … "Thank you very much for this amazing page and for everything. 1 foot = 12 inches, or 1 inch = 1/12 foot. If the pipe was made after WWII, try a comparison. Set up the formula for the circumference of a circle, as a function of its area. Student can also do an activity by inserting a circular object into a square shape with same diameter and side-length, respectively. If we open the circle to form a straight line, then the length of the straight line is the circumference. The sum of the small angle and the great angle will be 360 degrees. C = pi * d calculates the circumference (distance around the outside of the circle). Formula To Calculate Area of a Segment of a Circle; For this circle. ", "It helped very much - been a long time since college. By the formula of the surface area of the circle, we know; What are the circumference and the area of the circle if the radius is 7 cm. Standard formula to calculate the area of a circle is: A=πr². is the region occupied by the circle in a two-dimensional plane. Need help with finding the area of a circle? You convert inches to feet the same way to find the area of a circle as you do to find anything else. Symbols. radius provided or, when you know the Diameter: A = (π /4) × D2. To calculate the area, you just need to enter a positive numeric value in one of the 3 fields of the calculator. Make sure you know if you are measuring the small angle between the two radii or the greater angle outside them. To find the area of circle we have to know the radius or diameter of the circle. Half the diameter is the radius. It is usually represented by ‘r’ or ‘R’. To find the area using the diameter, or the distance from one side of the circle to the other, first divide the diameter in half to find the radius. ", "It was perfect, and I understood the process! ", "I love that it shows you different ways. How do I calculate the circumference of a circle? It can be determined easily using a formula, A = πr2, (Pi r-squared) where r is the radius of the circle. ", "This was very well explained and I like the examples on the PDF. Then the area for this circle, A, is equal to the product of pi and square of the radius. The area of circle is estimated to be the 80% of area of square, when the diameter of circle and length of side of square is same. The formula for the area of a circle is A = pi * r * r where r is the radius (diameter / 2). we use the following mathematical formula for calculating area and circumference of the circle In JavaScript: Area of Circle= radius * radius * PI circumference of the circle = 2 * radius * PI She has taught math at the elementary, middle, high school, and college levels. By using this service, some information may be shared with YouTube. A = Circle area; π = Pi = 3.14159… ø = Circle diameter; Diameter of Circle. Or suppose if you have to buy a table cloth, then how much portion of cloth is needed to cover it completely. Area of a circle can be visualized & proved using two methods, namely, Let us understand both the methods one-by-one-. How do I get the inside dimensions of a pipe with a total length of 45 inches? How can I calculate the number of chicks in a round box? We have. Assume for this example that the diameter of your circle is 20 inches. Welcome to How to Find the Area of a Circle with Mr. J! To compute it, we need to know the radius. Thus, the circumference of the circle is 44 cm. She has taught math at the elementary, middle, high school, and college levels. Perimeter: 2 * pi * radius. 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 and return it. How do I find the area if I was only given the diameter? Thanks to all authors for creating a page that has been read 5,217,159 times. Divide both sides of the equation by 2. In this article, let us discuss in detail about the area of a circle, surface area and its circumference with examples. Consider the circle shown in the fig. metre) with a built-up area (in sq. The length of rope which wraps around its boundary perfectly will be equal to its circumference, which can be measured by using the formula: π, read as ‘pi’ is defined as the ratio of the circumference of a circle to its diameter. In order to calculate the area of a segment of a circle, one should know how to calculate the area of the sector of the circle. It is called the “Circumference” of the circle. For example, if the radius of the circle is 6 inches, first you would square 6 and get 36. 30, Jul 19. Sometimes, the volume of a circle also defines the area of a circle. The answer is “No”. Remember: In this version, the central angle must be in degrees. If the object is a circle, and you know its circumference, you would divide the circumference by pi to find the diameter of the circle. Now how can we calculate the area for any circular object or space? The formulas for a circle’s segment are as follows: Area of a Segment of a Circle Formula. The three scenarios are: if the radius is known, if the diameter is known, if the circumference is known. I suspect that your problem includes the radius of a chick and the radius of the round box. The Area of Circle using Pointer can be calculated by using a formulae. Half the diameter is the radius. Divide the area in square centimeters by 10,000 to find the area in square meters. The radius of the circle is the line which joins the centre of the circle to the outer boundary. wikiHow is where trusted research and expert knowledge come together. 18, Jul 18. Find area of the larger circle when radius of the smaller circle and difference in the area is given. Find a pipe of the same material and exterior dimensions, and measure its interior. To define the circumference of the circle, knowledge of a term known as ‘pi’ is required. :)", "I was doing homework and got stuck on something. Let's write the program now. Area of Circle = πr2 or πd2/4, (square unit) where π = 22/7 or 3.14 BlueJ (area of circle) BlueJ (area of circle) How does one write a program to calculate the area of a circle in BlueJ? You will need to know some more data about the size of a chick and the size of the round box. Somewhere in your problem, you must be provided with the radius of each circle, or some way of determining the radius, diameter or circumference of each circle. As we found the value of r, now we can find the area; Subscribe to our BYJU’S YouTube channel to learn even the most difficult concepts in easy ways or visit our site to learn from wonderful animations and interactive videos. The base of the triangle will be equal to the circumference of the circle, and its height will be equal to the radius of the circle. See Area of a Circular Segment given the Segment Height. You wouldn't be asking, I presume, if you could see the inside. Square the radius and multiply by pi to find the area. Circumference of a Circle = πd Area of a Circle = πr 2 Square the radius and multiply by pi to find the area of the circle. Enter the radius of circle : 10.0 Area of circle : 314.00. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/6\/65\/Calculate-the-Area-of-a-Circle-Step-1-Version-6.jpg\/v4-460px-Calculate-the-Area-of-a-Circle-Step-1-Version-6.jpg","bigUrl":"\/images\/thumb\/6\/65\/Calculate-the-Area-of-a-Circle-Step-1-Version-6.jpg\/aid53808-v4-728px-Calculate-the-Area-of-a-Circle-Step-1-Version-6.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"