Answer: 16.8
============================================================
Step-by-step explanation:
The lower case letters represent the side lengths.
The uppercase letters represent the angles.
Side 'a' is opposite angle A
Side 'b' is opposite angle B
Side 'c' is opposite angle C
Angle A is 62 degrees because you would solve A+B+C = 180 for A. Or you can compute 180-B-C = 180-82-36 to get the same result for angle A.
Once you know the measure of angle A, you can use the law of sines
sin(A)/a = sin(B)/b
sin(62)/15 = sin(82)/b
b*sin(62) = 15*sin(82)
b = 15*sin(82)/sin(62)
b = 16.8232193521557 <<--- see note below
b = 16.8
note: use a calculator for that step. Make sure the calculator is in degree mode