The measure of the three angles of a triangle is given by 3x + 1, 2x -3, and 9x. What is the measure of the smallest angle? a- 29 degrees
b- 13 degrees
c- 40 degrees
d- 23 degrees

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.