Yes, these topics are all related. In fact it is how you can create simple pie charts with the Transform Panel and you don't need a calculator to do the math; the Transform Panel will do the math for you!
Open the Transform Panel under Window>Transform
Draw a circle.
On the right side of the circle is a handle that when you over over with the Selection Tool, will show a pie icon.
Click on the handle and move it around the circle. A tool hint will show up giving you the angles.
This is the result. A partial pie chart.
The handles correspond with the angles in the Transform Panel.
I want to end up with a Pie Chart like this. I am not going to draw this or pull the handles to get it exact, I am going to use Math!
Start with your original circle and type in the first angle the Percentage of the pie you want the piece to be (60%) x 3.6. The math looks like this: 60*3.6 then press return.
For every 1% of the pie chart it will be 3.6° of a circle. 100% = 360° in a complete circle.
The results are 60% of the Pie Chart showing.
Now you want the missing piece of the Pie Chart. Don't draw it...
Select the original piece of the pie and click on the swap pie piece highlighted here in the Transform Panel. (You have to click on the arrows in between the pie shapes). This will give you the other piece BUT you will lose the first pie piece!
You want both pieces of the pie without redrawing.
Select the piece of the pie and hold Otion or Alt and THEN click on the flip arrows and this will create a perfect opposite piece that fits perfectly in place!