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The formula for Area of a Circle is one of the most useful formula in math. The formula of Area of a Circle allows you to calculate the Area of a Circle very quickly. Proving the formula of Area of a Circle is left to college level math. The formula for Area of a Circle is not the same as the formula for the surface Area of a Circle which we shall discuss later. We will discuss formula for circumference and Area of a Circle in this section.

The formula for Area of a Circle uses two mathematical elements:

• the radius of the circle, and
• pi

The radius of a circle is the distance between the midpoint of the circle and the circumference of the circle. The radius of a circle is the same no matter where on the circumference of the circle you measure from. In the circle below, the radius of the circle is denoted by ‘r’. All the lines denoted by r are of the same length so it does not matter where you measure the r to as long as it is from the mid point of the circle.

Formula for Area of a Circle

The formula for Area of a Circle is given by:

The above formula to find area of a circle works for any radius r. Pi in the area of circle equation above is roughly 3.14159265

Formula for circumference of a Circle

The formula for the circumference of a circle is the same as the formula for the perimeter of a circle and is given by:

Now you can use the formula for area of a circle to calculate the area of a circle and the formula for the circumference of a circle to calculate the perimeter or circumference of a circle. The formula for the circumference of a circle is sometimes denoted by x d where d is the diameter of the circle. Since d = 2r the two formulas for the circumference of a circle is essentially the same.

How to find the area of a circle? The math formula for area of a circle helps you calculate the area of a circle in a quick and easy way. With the area of a circle equation, finding the area of a circle is fast, easy, and fun. If you need an area of a circle math worksheet, visit our sister website http://www.math-worksheets.info. We suggest that you read this section of area of a circle and learn how to calculate area of a circle before you go and get an area of a circle worksheet.

The area of circle equation is as follows:

For any circle, there is a radius which is the distance between the midpoint of the circle and the circumference of the circle. The radius of a circle is usually denoted by the letter ‘r’. All areas of circles require the use of the mathematical entity ‘pi’. Pi’s value is roughly 3.14159265 and it is denoted by the symbol:

Formula Area of a Circle

Area of a circle = r 2

In another word, the area of a circle is ‘pi r squared’. Remember this! It is the formula for calculating the area of a circle.

Area of a circle calculation example

Below is an example of how to find the area of a circle. With any circle, the first thing to do is find the radius of the circle. You can do this by measuring the distance from the center of the circle to any point on the circumference of the circle.

In this example of how to find the area of a circle, the radius of the circle is 10 cm or 10 centimeters. The area of the circle as given by the formula for the area of a circle above is: Area of the circle on the left hand side is

= x (10 cm) ²

= 3.14159265 x (10 cm) ²

= 314.159 cm ²

Note that the unit of an area of a circle is ’squared’ which represent the two dimensional nature of an area.