## Trigonometry (11th Edition) Clone

Let $\theta$ be the angle in radians. Let $A$ be the area of the sector. Then the ratio of the angle to $2\pi$ is equal to the ratio of the sector area to the area of the whole circle. $\frac{\theta}{2\pi} = \frac{A}{\pi ~r^2}$ $r^2 = \frac{2A}{\theta}$ $r = \sqrt{\frac{2A}{\theta}}$ $r = \sqrt{\frac{(2)(64~m^2)}{(\pi/6)}}$ $r = 15.6~m$ The radius of the circle is 15.6 m.