Question

Find the circumference of a circular window if the area is 100pi sq units

Answer 1

20pi sq units
.............

Answer 2

For this problem, using the area of the circle, we have to work backwards to find the radius to find the circumference

The area of the circle (A) = 100π units

A = 100π

The formula for area of a circle

A = πr²

Since we know what A is, lets plug it into the equation for area of a circle to solve for r

100π = πr²

Divide π from both sides to cancel them out

100 = r²

Take the square root of both sides to isolate r, the radius

r = 10

Now that we know what r is, let's plug it into the equation for the circumference of a circle

Circumference = 2πr

= 2π(10)

Multiply 2 and 10, because both are like terms

Circumference of the window = 20π