Calculating the area of a circle

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The area of a circle is the space occupied by the circle in a two-dimensional plane. There are three formulas for calculating the area of a circle.


Given a circle's radius, the formula for calculating its area asserts that:

Area formula

Pi (π) = 3.14. It is the ratio of circumference to diameter of any circle.

Circle #2:

Given a circle's diameter

Area formula diameter #3:

Given a circle's circumference

Area formula circumference


A circle has a surface area of 254.34 square yards. Calculate its radius.


A = πr^2

254.34 = 3.14 xr^2

Now, divide both sides by 3.14.

r^2 = 254.34/3.14 = 81

Find the square root of both sides.

r = √81 = 9

r = -9, 9

Since the radius cannot be negative, the correct answer is 9.

Answer: Circle’s radius is 9.