Expand this expression (x-y)²

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°?

Hundred and tens tables to make 430 in five different ways

How would you find the height of points on the circle? the topic is trigonometry.