Question

Solve for the radius

Answer 1

To solve for the radius(r), you need to isolate/get the radius by itself in the equation:

$A=\frac{1}{2} \pi r^2$   Multiply the inverse of 1/2, which is 2/1 or 2 on both sides

$(2)A=(2)\frac{1}{2} \pi r^2$

2A = πr²     Divide π on both sides

$\frac{2A}{\pi } =\frac{\pi r^2}{\pi }$

$\frac{2A}{\pi } =r^2$     Now square root √ both sides to get "r" by itself

$\sqrt{\frac{2A}{\pi } } =\sqrt{r^2}$

$\sqrt{\frac{2A}{\pi } } =r$     Your answer is A