Question

Are all equilateral triangles isosceles ??

Answer 1

an isosceles triangle is one with 2 equal sides. Therefore every equilateral triangle is isosceles but not every isosceles triangle is equilateral.

Answer 2

Yes
An Equilateral triangle is a triangle in which all the three sides are equal. and are inclined at 60°.

An Isosceles triangle is a triangle in which any two sides are equal and that two sides are inclined at the equal angle.

As in the equilateral triangle the three sides are equal therefore we can say that one of the pair of the two sides ate equal and thus an equilateral triangle also represent an isosceles triangle.