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?