9. There are 40 houses in a neighborhood.
Company X provides electricity to of the houses.
Company Y provides electricity to į of the houses.
Company Z provides electricity to the remaining houses.
In this neighborhood, Company Z provides electricity to –
21

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.