Find slope of line perpendicular to given line x=3

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°?

Find the greatest common factor of the followig monomials 21u^5v,3u^4v^6, and 3u^2v^5

How much orange juice do you need to make 2 servings of lemony orange slush?