If <A and <B are supplementary angles, and m<B is half as large as angle A, what is the m<A?

Answer 1

Supplementary angles add up to 180 so

A +B = 180

B = A/2

Substitution

A + A/2 = 180

2A/2 + A/2 = 180

common denominator of 2

3A/2 = 180

Multiply both sides by 2/3

A = 120

B = 60