Two trucks leave a warehouse at the same time. one travels due east at an average speed of 50 miles per hour, and the other travels due west at an average speed of 51 miles per hour. after how many hours will the two trucks be 707 miles apart?

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.