Question

Find the measure of an angle whose supplement is itself.

Answer 1

Let the measure of an angle be $x^{\circ }$, then the measure of its supplement is also $x^{\circ }$

We know that the sum of the measures of the angle and its supplement is ${180}^{\circ }$

$\therefore x^{\circ }+x^{\circ }={180}^{\circ }$

$\Rightarrow 2x^{\circ }={180}^{\circ }$

$\Rightarrow x^{\circ }=\frac{{180}^{\circ }}{2}={90}^{\circ }$