Geometry

Question Analysis:
This question is testing the fundamental definition and property of an isosceles triangle.

Key Concept Explanation: An isosceles triangle is defined as a triangle that has at least two equal sides.
The angles opposite the equal sides in an isosceles triangle are called the base angles and they are equal.
Conversely, if a triangle has two equal angles, then the sides opposite those angles are also equal, making the triangle isosceles.
This is known as the converse of the isosceles triangle theorem.

Step - by - Step Solution:
Let's assume that in a triangle ABC, angles  and