Question

If $\angle P$ and $\angle Q$ are complementary in a triangle PQR, then the measure of $\angle R$ is

• A. ${45}^{\circ }$
• B. ${60}^{\circ }$
• C. ${75}^{\circ }$
• D. ${90}^{\circ }$

Answer 1

The correct option is D ${90}^{\circ }$

Complementary angles means when angles add up to 90 degree.
Since sum of a triangle is 180 degree, so if two angles angle P and angle Q are complementary then angle R will be 90 degree
$\angle P+\angle Q+\angle R={180}^0$
$90+\angle R={180}^0$
$\angle R={90}^0$