Question

Two angles of a quadrilateral measure ${85}^0$ and ${75}^0$ respectively. The other two angles are equal. Find the measure of each of these equal angles.

Answer 1

Sum of 4 angles of a quadrilateral - ${360}^0$
Sum of two angles = ${85}^0+{75}^0={160}^0$
$\therefore$ Sum of other two angles = ${360}^0-{160}^0={200}^0$
But each of these two angles are equal
$\therefore$ Measure of each equal angle = $\frac{{200}^0}{2}$
= ${100}^0$