What is the measure of Q

m<Q = m<S + m<T
Since the triangle is isosceles, angles S and T are congruent.
m<Q = m<S + m<S
m<Q = 2m<S
m<Q = 2 * 74
m<Q = 148
The answer is option B. 148°.
<S = <T because The Angles opposite to equal sides are equal .
.
<Q = <S + <T
<Q = 74 + 74
<Q = 148°
.
Hence the answer B