Question

If the exterior angle of a triangle is $130°$ and its interior opposite angles are equal, then measure of each interior opposite angle is

• A. $55°$
• B. $65°$
• C. $50°$
• D. $60°$

Answer 1

The correct option is B

$65°$

Compute the interior opposite angle.

Given: Interior opposite angles are equal.

Let's plot the figure,

Let us assume the interior opposite angles$\angle A$ and $\angle B$ are $Q$.

Using exterior angle property,

$$\begin{gathered} 130°=\angle A+\angle B \\ \Rightarrow 130°=Q+Q \\ \Rightarrow 2Q=130° \\ \Rightarrow Q=\frac{130°}{2} \\ \Rightarrow Q=65° \end{gathered}$$

Hence, the measure of each interior opposite angle is $65°$.