As a block of ice melts, its weight changes from lb to 2 1/2 lb to 1/2/b. This change takes 1/2
hr.
The ice melts at a constant rate. At what rate
does the weight of the ice change?​

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.