Quadrilateral abcd is an isosceles trapezoid. if || , ab = m + 6, cd = 3m + 2, bc = 3m, and ad = 7m – 16, solve for m.

The perimeter of △cde is 55 cm. a rhombus dmfn is inscribed in this triangle so that vertices m, f, and n lie on the sides cd , ce , and de respectively. find cd and de if cf=8 cm and ef=12 cm. the answer is not cd=20 and de=15. i have tried that one, it does not work.