$$ \begin{aligned} A & =\frac{1}{2} \pi r^{2} \ A & =\frac{1}{2} \pi()^{2} \quad ext { Replace } r ext { with } 30 .\end{aligned} $$

Question

$$ \begin{aligned} A & =\frac{1}{2} \pi r^{2} \ A & =\frac{1}{2} \pi()^{2} \quad 	ext { Replace } r 	ext { with } 30 .\end{aligned} $$

Cole George · Accepted Answer

Substitute $$ r=30 $$ into the expression $$ \frac{1}{2} \pi r^{2} $$ gives $$ 450\pi $$.

\( \begin{aligned} A & =\frac{1}{2} \pi r^{2} \\ A & =\frac{1}{2} \pi()^{2} \quad \text { Replace } r \text { with } 30 .\end{aligned} \)