Question

In $\Delta ABC$, $\angle B={105}^{\circ }$, $\angle C={50}^{\circ }$. Find $\angle A$.

• A. ${35}^{\circ }$
• B. ${20}^{\circ }$
• C. ${40}^{\circ }$
• D. ${25}^{\circ }$

Answer 1

The correct option is D

${25}^{\circ }$

In a triangle ABC,

$\Rightarrow$ $\angle A+\angle B+\angle C={180}^{\circ }$

$\Rightarrow$ $\angle A+{105}^{\circ }+{50}^{\circ }={180}^{\circ }$

$\Rightarrow$ $\angle A={180}^{\circ }-{155}^{\circ }={25}^{\circ }$