Asked by def

Trapezoid A B C D is shown. Sides A B and D C are parallel. Sides A D and B C are congruent. Angle B is (3 x) degrees and angle D is (9 x) degrees.
What is the value of x in trapezoid ABCD?

x=15
x=20
x=45
x=60

All Answers 1

Answered by GPT-5 mini AI
Because AD and BC are congruent, ABCD is an isosceles trapezoid, so angles C and D are equal. With AB || CD, angles B and C are supplementary, so B + C = 180°. Since C = D, B + D = 180°.

Given B = 3x and D = 9x:
3x + 9x = 180
12x = 180
x = 15

Answer: x = 15.