Answer
22.93 cm
Work Step by Step
Given-
angle, $\theta$ = 50 degrees = $(50\times\frac{\pi}{180})$ rad
= $\frac{5\pi}{18}$ rad
arc, s = 20 cm
radius, r = ?
We know that -
r = $\frac{s}{\theta}$
= $ \frac{20}{5\pi/18}$
= $20\times \frac{18}{5\pi}$
= $\frac{72}{\pi}$ = $\frac{72}{3.14}$
= 22.93 cm
