Question

Quadrilateral ABCD is a parallelogram.

Given that m/B= (4x-9) and m/D= (3x+3), find mZB and mZC.
Enter your answers in degrees by entering deg after any value that is in degrees.
m/B

Answer 1

∠ B = 39° , ∠ C = 141°

Explanation:

in a parallelogram

• opposite angles are congruent

• consecutive angles are supplementary

so

∠ B = ∠ D

4x - 9 = 3x + 3 ( subtract 3x from both sides )

x - 9 = 3 ( add 9 to both sides )

x = 12

Then

∠ B = 4x - 9 = 4(12) - 9 = 48 - 9 = 39°

and

∠ B + ∠ C = 180°

39° + ∠ C = 180° ( subtract 39° from both sides )

∠ C = 141°