Known: as shown in the figure, in the isosceles trapezoid ABCD, ab = CD, ad ‖ BC, e is a point outside the trapezoid, and EA = ed, prove: EB = EC

Known: as shown in the figure, in the isosceles trapezoid ABCD, ab = CD, ad ‖ BC, e is a point outside the trapezoid, and EA = ed, prove: EB = EC

It is proved that in the isosceles trapezoid ABCD, ab = CD, ∠ bad = ∠ CDA. ∵ EA = ed,  ead = ∠ EDA. ≌ EAB = ∠ EDC. (2 points) in △ Abe and △ DCE, ≌ AB = DC ≌ EAB = edcea = ed, ≌ Abe ≌ DCE. (5 points) ≌ EB = EC. (6 points)