The measure of ∠A is twice the measure of ∠B and the measure of ∠B is twice the measure of ∠C. If ∠A and ∠C are supplementary, find m∠B .

Answer 1

m∠B = 2m∠C

m∠A = 2m∠B

m∠A = 4m∠C

m∠A + m∠C = 180°

4m∠C + m∠C = 180º

5m∠C = 180º

m∠C = 36º

2m∠C = 72º

Answer 2

a=2b

b=2c

a+c=120

b=2(120-a)

b=240-2a