Answer:
[tex] \theta = 7 .2\degree [/tex]
Step-by-step explanation:
[tex]area = \frac{\theta}{360} \times \pi {r}^{2} \\ 27.72 = \frac{\theta}{360} \times \pi \times {21}^{2} \\ 27.72 = \frac{\theta}{360} \times \pi \times 441 \\ \frac{27.72 \times 360}{441\pi} = \theta \\ \frac{9979.2}{1385.4} = \theta \\ \\ 7 .2\degree = \theta[/tex]
