Quadrilateral ABCD is a parallelogram such that ∠A=2x and ∠B=x+6. What is the measure of ∠B?

Problem 1

Angles A and B are adjacent in parallelogram ABCD. For any parallelogram, adjacent angles are supplementary.

A+B = 180

2x+(x+6) = 180

3x+6 = 180

3x = 180-6

3x = 174

x = 174/3

x = 58

Use this x value to find angles A and B

angle A = 2x = 2*58 = 116 degrees

angle B =  x+6 = 58+6 = 64 degrees

 64 degrees

Problem 2

Let y be the measure of the unknown angle that's supplementary to the 42 degree angle. This must mean that,

y+42 = 180

y = 180-42

y = 138 degrees

D) 138 degrees

45

step-by-step explanation:

answer: 2x + 2 − 2 = 10 − 2; subtraction property of equality

step-by-step explanation: