Question

a triangle is equilateral if
______ sides are the same length.
no
all 3
at least 2
only 2

Explanation:

An equilateral triangle is defined as a triangle where every one of its three sides has equal length. "At least 2" describes an isosceles triangle, "only 2" also fits isosceles, and "no" does not match any valid equal-sided triangle definition.

Answer:

all 3