Question

choose the correct answer below
a. no, because while some equilateral triangles are isosceles, not all equilateral triangles are isosceles.
b. no, because equilateral triangles have nothing in common with isosceles triangles
c. no, because an equilateral triangle cannot be an isosceles triangle
d. yes, because according to the definition, isosceles triangles have at least two congruent sides. equilateral triangles have three congruent sides. therefore, they have at least two congruent sides and are isosceles

Explanation:

An isosceles triangle is defined as a triangle with at least two congruent sides. An equilateral triangle has three congruent sides, which means it has at least two congruent sides. So all equilateral triangles are isosceles.

Answer:

D. Yes, because according to the definition, isosceles triangles have at least two congruent sides. Equilateral triangles have three congruent sides. Therefore, they have at least two congruent sides and are isosceles.