A10-foot ladder is to be placed against the side of a building. the base of the ladder must be placed at an angle of 72 degrees with the level ground for secure footing find to the nearest inch how far the base of the ladder should be from the side of the building? ?

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.