To estimate how many miles you are from a thunderstorm, count the seconds between when you see lightning and when you hear thunder. then divide by 5. write and solve an equation to determine how many seconds you would count for a thuderstorm that is 2 miles away.

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.