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?

B.At least two of the angles are congruent.

Step-by-step explanation:

Isosceles triangle : It is that triangle in which two sides of triangle are same.

In other words ,we can say that

Isosceles triangle is that triangle in which two angles of the  triangle are equal.

A.All three angles are congruent.

It is not true because it is not necessary that all three angles are congruent.

B.At least two of the angles are congruent.

It is true by definition of isosceles triangle.

C.The vertex angle is a right angle.

It is not true because it is not necessary that the vertex angle is a right angle.

D.The vertex angle is obtuse.

It is not true because it is not necessary that the vertex angle is a right angle.