Solve A=4*pi/4*(d)^2

$$A = 4 \times \frac { \pi } { 4 } \times ( d ) ^ { 2 }$$

Solve for A

$$A=\pi d^{2}$$

Solution Steps

Express 4\times \frac{\pi }{4} as a single fraction.

$$A=\frac{4\pi }{4}d^{2}$$

Cancel out 4 and 4.

$$A=\pi d^{2}$$

Solve for d (complex solution)

$$d=-\sqrt{\frac{A}{\pi }}$$

$$d=\sqrt{\frac{A}{\pi }}$$

Solve for d

$$d=\sqrt{\frac{A}{\pi }}$$

$$d=-\sqrt{\frac{A}{\pi }}\text{, }A\geq 0$$