Textbook Problem

Determine whether the statement is true or false.

a) The area of a circle with radius length r is given by $A=\pi r^2$. $\underset{\_}{}$

b) With lengths of the corresponding sides of similar polygons having the ratio $\frac{s_1}{s_2}=\frac{1}{2}$, the ratio of their areas is $\frac{A_1}{A_2}=\frac{1}{2}$. $\underset{\_}{}$