Question

In $\Delta$ ABC, seg AB $\cong$ seg AC and $\angle A={80}^{\circ }$ then find $\angle B$ and $\angle C$

• A. $\angle B={50}^{\circ },\angle C={60}^{\circ }$
• B. $\angle B={50}^{\circ },\angle C={30}^{\circ }$
• C. $\angle B={50}^{\circ },\angle C={40}^{\circ }$
• D. $\angle B={50}^{\circ },\angle C={50}^{\circ }$

Answer 1

The correct option is D $\angle B={50}^{\circ },\angle C={50}^{\circ }$

Given: seg AB $\cong$ seg AC
Hence, $\angle ABC=\angle ACB=x$ (Isosceles triangle property)
Sum of angles of the triangle = 180
$\angle ABC+\angle BAC+\angle ACB=180$
$x+80+x=180$
$2x=100$
$x={50}^{\circ }$
Thus, $\angle B=\angle C={50}^{\circ }$