Question:
The sum of two angles of a triangle is 116° and their difference is 24°. Find the measure of each angle of the triangle.
Solution:
Let $\angle A+\angle B=116^{\circ}$ and $\angle A-\angle B=24^{\circ}$
Then,
$\therefore \angle A+\angle B+\angle A-\angle B=(116+24)^{\circ}$
$\Rightarrow 2 \angle A=140^{\circ}$
$\Rightarrow \angle A=70^{\circ}$
$\therefore \angle B=116^{\circ}-\angle A$
$=(116-70)^{\circ}$
$=46^{\circ}$
Also, in ∆ ABC:
$\angle A+\angle B+\angle C=180^{\circ} \quad[$ Sum of the angles of a triangle $]$
$\Rightarrow 70^{\circ}+46^{\circ}+\angle C=180^{\circ}$
$\Rightarrow \angle C=64^{\circ}$