Astandard coffee mug has a capacity of 16 fluid ounces if annie needs to fill 26 mugs with coffee how many total quarts of coffee does she need

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.