Question

An angle in an isosceles triangle is ${80}^{\circ }$. Find the other two angles corresponding to equal sides.

• A. ${40}^{\circ },{60}^{\circ }$
• B. ${50}^{\circ },{50}^{\circ }$
• C. ${30}^{\circ },{70}^{\circ }$
• D. 80°,20°.

Answer 1

The correct option is B

${50}^{\circ },{50}^{\circ }$

In an isosceles triangle, two sides are equal and the angles opposite to the equal sides are also equal.

Let the measure of the angle be $\theta$

From angle sum property, $\theta +\theta +{80}^{\circ }=180$

$\Rightarrow 2\theta ={100}^{\circ }$

$\Rightarrow \theta =\frac{100}{2}={50}^{\circ }$

So, the other two angles will be equal to ${50}^{\circ }$