Since the interior is 170 the exteriro must be 10 degrees. There is a total of 360 degrees so 360/10=36 or 36 sides.
9.This is because it goes through the whole circle passing through the centre point. at the full width
The rest are pretty easy. I'm sure you can manage. Good luck!
.94 times 2.6 would be 2.4
I think its c your welcome