The picture below shows a right-triangle-shaped charging stand for a gaming system:
60
DC
B
8
in.
Which expression shows the length of side AB?
8(cos 60)
Sin69
cos 69
8(tan 60%

Given: ae ≅ ce ; de ≅ be prove: abcd is a parallelogram. we have that ab || dc. by a similar argument used to prove that △aeb ≅ △ced, we can show that △ ≅ △ceb by. so, ∠cad ≅ ∠ by cpctc. therefore, ad || bc by the converse of the theorem. since both pair of opposite sides are parallel, quadrilateral abcd is a parallelogram.