Clarity over use of param startAngle - values of 0 to 360

[RoundSparrow]

from code:
"startAngle start angle in degrees"

It's not clear to me how this is "human readable". Maybe I'm making a big geometry mistake in asking this question, but here goes ;)

1. Is it not the natural common-sense thinking that the value of an angle should be 0..360?
2. Is there some kind of multiplication going on to account for screen density? Should the factor be adjusted/variable?
3. Comments could explain home/origin position? is it at 12-o'clock or 3-o'clock?

The sample application uses 720 as a value. Currently line 48 of MainActivity.java code. It just doesn't seem intuitive to me why that ends up at the 3-o'clock position of a pie... for multiple reasons given. Would it not seem more like this is 90 using a compass?

Thank you for the code and time.