Answer:
Base
Explanation:
A triangle is a polygon with three sides and three angles. There are different types of triangles which are scalene triangle, isosceles triangle,, equilateral triangle etc..
An isosceles triangle is a triangle in which two of the sides are equal, also two angles are equal. The two equal sides of the isosceles triangle are called base while the other side is the base.
The base of an Isosceles triangle is the side included between the pair of congruent angles.