Question

Find the unknown marked angle, in the triangle drawn below.

• A. ${95}^{\circ }$
• B. ${105}^{\circ }$
• C. ${80}^{\circ }$
• D. ${115}^{\circ }$

Answer 1

The correct option is C ${80}^{\circ }$

We know that, Exterior angle of a triangle is always equal to the sum of its two interior opposite angles (Exterior Angle Property) .
So,
$\Rightarrow {110}^{\circ }=x+{30}^{\circ }$
$\Rightarrow x={110}^{\circ }–{30}^{\circ }$
$\Rightarrow x={80}^{\circ }$