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.
Thank you for your help.
