I can barely see your questions! Try and make them a bit larger next time.

15)

Area= 1/2 x 13^2 x sin(60) =73.2 in^2

16)

Tan(x) = 86

x =Arctan(86) =89.33 degrees.

17)

Cos(x) =7/14 = 1/2

x =Arccos(1/2) =60 degrees

18)

Sin(x) =2 / 25

x =Arcsin(2/25) =4.59 degrees.