Answer: For problem 8:
sin A/a sinB/b = sinC/c
so sin50/15 = sinB/12
0.766/15 =sinB/12
0.051066 = sin B/12
sin B = 0.6128
B = 37.79 degrees
sum of angles must equal 180 deg therefore C = 180-50-37.79 = 92.21 degrees and .766/15 = sin92.21/c
.051066= 0.99925/c
c = .99925/0.051066 = 19.567
Problems 9 and 10 can also be done with the same method as problem 8.For problem 8:
sin A/a sinB/b = sinC/c
so sin50/15 = sinB/12
0.766/15 =sinB/12
0.051066 = sin B/12
sin B = 0.6128
B = 37.79 degrees
sum of angles must equal 180 deg therefore C = 180-50-37.79 = 92.21 degrees and .766/15 = sin92.21/c
.051066= 0.99925/c
c = .99925/0.051066 = 19.567
Problems 9 and 10 can also be done with the same method as problem 8.
This is not my answer. I shall give credit to the rightful owner of these answers.