a set of angels has a ratio of 5:2 . If the larger angle measures 105 degrees then what is the measure of the smaller angle

When you are making a circle graph by hand, how do you convert a number for a part into its corresponding angle measure in the circle graph? when you are making a circle graph by hand, what should you do if one of your angle measures is greater than 180°?

Which one ? is the answer and how to find this answer

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