Question

What is the measure of ZRST?

Answer 1

$\huge\textsf{D.}\ \boxed{79^\circ}$

$\angle RST$ is an inscribed angle. This means that the measure of the angle is equal to half the measure of the intercepted arc.

$\begin{aligned}m\angle RST&=\frac{1}{2}m\widehat{RT}\\&=\frac{1}{2}(158^\circ)\\&=\boxed{79^\circ}\end{aligned}$