When two of its non-parallel sides are congruent
true
true
true
True.
An isosceles triangle is not a regular polygon because it has only 2 equal sides but an equilateral triangle is a regular polygon because it has 3 equal sides and 3 equal angles.
When two of its non-parallel sides are congruent
true
true
true
true
false
False
True.
True
TRUE
true