Answer:
[tex] = 31.76 {units}^{2} [/tex]
*this is the correct answer but the correct answer is not there.
Step-by-step explanation:
[tex]2\pi \: r = 20 \\ \frac{2\pi \: r}{2} = \frac{20}{2} \\ \pi \: r = 10 \\ \frac{\pi \: r}{\pi} = \frac{10}{\pi} \\ r = 3.18 \: \: units[/tex]
[tex]area = \pi {r}^{2} \\ = \pi \times 3.18 \times 3.18 \\ = 31.76 {units}^{2} [/tex]