Write the value of
a+b. b+c. c+a
a. b. c
(X. ). ( x. ). (. X. )
__ _. X . X.
b. c. a
(X ). (. X. ). (. X. )

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.