Question

The circumference of a circle is 20 m. What is the area, in square meters? Express

your answer in terms of pi?

Answer 1

Explanation:

the circumference of a circle is

2pi×r

or

pi×d

r being the radius, d being the diameter.

remember, d = 2r.

the area of a circle is

pi×r²

so, now we know the circumference of the circle (20 m). and that means

2pi×r = 20

pi×r = 10

r = 10/pi

this we use now in the formula for the area :

pi×r² = pi×(10/pi)² = pi×100/pi² = 100/pi m²

the area is 100/pi m².