Question

The measure of ∠A is 12° more than three times the measure of ∠B. If A and B are supplementary angles, find the measure of ∠A.
137°
138°
139°
140°

Answer 1

let B = x A = 3x + 12

then x + 3x + 12 = 180 (supplementary angles)

solve the equation

4x + 12 = 180

to find B

then tripe it and add 12 to find A

Answer 2

the above ans is correct
let B = x A = 3x + 12

then x + 3x + 12 = 180 (supplementary angles)

solve the equation

4x + 12 = 180

to find B

then tripe it and add 12 to find A

Answer 3

wow... well done Rohangrr... nice copy and paste job

Answer 4

Let m<A = x
and m<B = 180 - x given that the angles are supplementary

m<A = 3(m<B) + 12
x = 3(180 - x) + 12
x = 540 - 3x + 12
4x = 552
x = 138

m<A = 138
m<B = 180 - 138 = 42.
138° ---------> Answer