A trapezoid is any four-sided figure that has at least one pair of parallel sides. Pictured below is trapezoid ABCD whose side AD is parallel to side BC. Line m is the perpendicular bisector of side AD, with midpoint at E. Line m also bisects side BC with midpoint at F. a) Explain why line m must also be perpendicular to side BC.
b) What rigid motion could be used to show that AB=CD? Explain how the mapping would work.

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.

answer: answer is b.

[m < b = 120º]

step-by-step explanation:

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step-by-step explanation: