1) 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 = 105 −x/2
∠D = 40 + 4x
Choices
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
AD = 40 +x/2
BC = 3x − 10
CD = 3x + 35
Choices
A. x=2
B. x=5
C. X=10
D. x=20