Question

ABCD is a parallelogram. Find the measure of B.

Answer 1

15

Explanation:

9x-5=10x-20

X-20=-5

X=15

Answer 2

∠B = 130°

Explanation:

The opposite angles of a parallelogram are congruent, thus

∠D = ∠B, that is

10x - 20 = 9x - 5 ( subtract 9x from both sides )

x - 20 = - 5 ( add 20 to both sides )

x = 15

Hence

∠B = 9x - 5 = (9 × 15) - 5 = 135 - 5 = 130°