Question

What is the exact area of a circle with a diameter of 20 cm?

Answer 1

Hi there! The answer is 100πcm^2

The radius of a circle can be found by dividing the diameter by 2. In other words : the radius is half of the diameter.
Therefore, the radius of a circle with a diameter of 20 cm is 10 cm.

The exact area of a circle can be found using the following formula:
$a = \pi \times \: {r}^{2} \\ with \\ a = area \\ r = radius$

In order to find our answer, we need to plug in the data from the question.
$a = \pi \: \times {10}^{2} = 100\pi$

Hence, the answer is 100πcm^2.