Answer
(a) $A(r)= 4r^2$
(b) $p(r)= 8r$
Work Step by Step
(a) The side length $s$ of the square is equal to twice the radius of the circle. Thus, $s=2r$.
The area $A$ of a square is given by the formula $A=s^2$. Thus, the area of the given square is:
$A(r)=(2r)^2=4r^2$
(b) The perimeter $p$ of a square is given by the formula $p=4s$ where $s$ is the side length.
Thus, the perimeter of the given square is :
$p(r)=4(2r)=8r$
