State the dimensions of the matrix. identify the indicated element​

If jaime wants to find 60% of 320, which table should he use?

Asap! i'm not good math and i'm lost.

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.