Can someone me with this question, i don’t understand

Suppose a triangle has two sides of length 32 and 35, and that the angle between these two sides is 120°. which equation should you solve to find the length of the third side of the triangle?

Given a: b and b: c, find a: b: c. write the ratio in simplest form. a: b=6: 10 and b: c=21: 33

700 miles the train takes 5 hours to a travel the distance at what unit rate is the train traveling?