Question

Two angles of a triangle are of measures ${65}^{\circ }$ and ${25}^{\circ }$. Find the measures of the third angle.

• A. ${90}^{\circ }$
• B. ${75}^{\circ }$
• C. ${60}^{\circ }$
• D. ${30}^{\circ }$

Answer 1

The correct option is A ${90}^{\circ }$

Let $ABC$ be a triangle such that $\angle ={65}^{\circ }\text{and}\angle ={25}^{\circ }$.

Now, we have to find the measure of the third angle $A$.

By the angle sum property of triangles, we get,

$\angle A+\angle B+\angle C=180$

$\angle A+65+25=180$

$\angle A+90=180$

$\angle A=180-90$

$\angle A={90}^{\circ }$