Which statement is not true of an isosceles triangle?

a. the measure of a base angle and the measure of its vertex angle can never be equal.

b. it has a base that is opposite a vertex angle.

c. the sides opposite its base angles are congruent.

d. the angles opposite its legs are congruent.

2. angles qrt and qst both measures 156 degrees.

step-by-step explanation:  

we have been given a diagram of a circle and we are told that measure of arc qvt is 156 degrees.  

we can see from our given diagram that angle qrt and angle qst subtends to arc qvt.

since we know that angles subtended by the same arc at the circumference are always equal.

by angle subtended by same arc theorem, measure of angle qrt and angle qst will be equal to the measure of arc qvt.

therefore, angles qrt and qst both measures 156 degrees and 2nd statement is the correct choice.