Question

The sum of two angles of a triangle is equal to its third angle. Determine the measure of the third angle.

Answer 1

Consider $△ABC$,

Then according to the given condition, $\angle A=\angle B+\angle C$

Sum of all the interior angles of the triangle is ${180}^o$

Hence, $\angle A+\angle B+\angle C={180}^o$
$\angle A+\angle A={180}^o$

$2\angle A={180}^o$

$\Rightarrow \angle A={90}^0$