For the first one, the remaining angle in the triangle is 17°
So, using the Law of Sines, we have
d/sin(38) = 10/sin(17) multiply both sides by sin(38)
d =10*sin(38)/sin(17) = about 21 ft.
The other two problems are similar to this one I just worked (using The Law of Cosines):
http://web2.0calc.com/questions/hey-it-s-laila-again-i-need-help-with-another-question-there-is-a-picture-in-this-one-too
