Kiersten runs a website that people learn programming. every month, kiersten receives a subscription fee of $10 from each of the subscribers to her website. last month, the website had 100 subscribers. this month, 30 new members joined the website, and 10 members cancelled their subscription

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.