Which equation can be used to solve for x in the following diagram

Pick the description of a geometric object that best matches the real world object box for a deck of card

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.

If jack has 16 aplles and gives it to 5 friends how many does each get