Question

What is always true about the angles of an isosceles triangle?

All three angles are congruent.
At least two of the angles are congruent.
The vertex angle is a right angle.
The vertex angle is obtuse.

Answer 1

At least two of the angles are congruent.

In an isosceles triangle the base angles (the angles opposite the equal sides) are equal. The other options (all three congruent, vertex right, vertex obtuse) need not be true.