Question

To construct a $△$ ABC given AB $=7$ cm, $\angle A={35}^{\circ },\angle B={40}^{\circ }$ what will be the measure of third angle is_____ .

• A. ${95}^{\circ }$
• B. ${110}^{\circ }$
• C. ${105}^{\circ }$
• D. ${100}^{\circ }$

Answer 1

The correct option is C ${105}^{\circ }$

By angle sum property of triangles,
$\angle A+\angle B+\angle C={180}^{\circ }$
$\therefore \angle C={180}^{\circ }-\angle B–\angle A$
$={180}^{\circ }–{35}^{\circ }–{40}^{\circ }$
$\therefore \angle C={105}^{\circ }$