Question

what is always true about the angles of an isosceles triangle?
at least two of the angles are congruent.
all three angles are congruent.
the vertex angle is obtuse.
the vertex angle is a right angle.

Explanation:

An isosceles triangle is defined as a triangle with at least two equal (congruent) sides, and by the Isosceles Triangle Theorem, the angles opposite those equal sides are congruent. So at least two angles are congruent. "All three angles are congruent" is true for equilateral triangles (a special case of isosceles), but not all isosceles triangles. The vertex angle can be acute, right, or obtuse, so the last two options are not always true.

Answer:

At least two of the angles are congruent.