As θ increases from -π/2 to 0 radians, the value of the cos θ will:
A) Decrease from 1 to 0
B) Decrease from 0 to -1
C) Increase from -1 to 0
D) Increase from 0 to 1

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.