Which pairs of number lie on opposite sides of 0 on a number line? a: 8,7 b -10,10 c: -4,9 d: -8,-15 e: -21,21 f: 2,200

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.