The quadrilateral ABCD is a parallelogram if pairs of consecutive angles are supplementary. Given the angle measures, prove that quadrilateral ABCD is a parallelogram by finding the value of x. ∠A = 120 − 2x
∠B = 70 + x
∠ C = 1 0 5 − 2x
∠D = 40 + 4x

A) x = 2
B) x = 5
C) x = 10
D) x = 20

2) The quadrilateral ABCD is a parallelogram if both pairs of opposite sides are congruent. Given the side lengths, prove that quadrilateral ABCD is a parallelogram by finding the value of x.

AB = 2x + 55
A D = 4 0 + 2x
BC = 3x − 10
CD = 3x + 35

A) x = 2
B) x = 5
C) x = 10
D) x = 20