#### Answer

C = 62.8 cm
A = 314 $cm^{2}$

#### Work Step by Step

Given the diameter of the circle = 20 cm
As we know radius of the circle = $\frac{d}{2}$ = $\frac{20}{2}$= 10 cm
The circumference of the circle is given by the formula
c= $\pi$ d = 2$\pi$ r
=2 * 3.14 * 10 = 62.8 cm
The area A of a circle whose radius has length r is given by
A = $\pi r^{2}$cm
= 3.14 * $10^{2}$
= 3.14 * 100
=314 $cm^{2}$