Question

Can an equilateral triangle also be isosceles?

Answer 1

Use the definition of equilateral triangle and isosceles triangle:

By definition of equilateral triangle, a triangle is equilateral if all the sides and angles of a triangle are equal.

By definition of isosceles triangle, a triangle is isosceles if two sides and corresponding base angles are equal.

As two of the base angle of equilateral triangle are equal and 2 sides are also equal

Therefore, equilateral triangle be isosceles.