geometry
posted by joe .
in the diagram below of triangle abc, de is a midsegment of triangle abc, de=7, ab=10, and bc=13.find the perimeter

Well, we don't have a diagram, but that won't stop us in this case. A midsegment of a triangle is parallel to one of the sides, and half its length.
Since de=7 is not half of ab=10, nor of bd=13, then that means that it must be half of ac. So, ac=14, and the perimeter is
p = 10 + 13 + 14 = 37 
joel