Can't see the graph can you make it more clear?
Start at (0, 72), then (1, 64), (2, 56), ETC. I hope you see the pattern! Do it until you reach (9, 0)
In a circle, the internal vertical angles have a formula of

In this case, the formula would be:

We know that whole circle is 12x. And 12x is equal to 360°. When we put that into equation:


If x is 30°:

So, angle 7 is 90°.
2x^2+3. the 2x cancel out and the rest is combining like terms
Idk really I enjoyed this mathematics