Question

If the diameter of a circle is 20 cm, what is the area?

O
10п cm2
O 20 п cm
50 п cm2
O 100 п cm2

Answer 1

Half of 20 is 10(New radius)

10^2(radius squared) = 100

100pi is your next step, which is 100π cm2

Formula area of a circle:

πr^2

pi(3.14 or 22/7 depending on what they tell you to use for pi) x radius(half of your diameter or given radius) squared(to the power of 2)

Pi x radius being squared

Answer 2

A = 100 pi cm^2

Explanation:

A = pi(r^2)

A = pi(10^2)

A = pi(100)

A = 314.16 '

Convert to pi units.

314.16 ---> 100pi cm^2