Which expression is equivalent to √36/25?

a) 6/25
b) 5/6
c) 6/5
d) 36/25

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.