its simple....just use the sides of the polygon minus by 2 and multiply by 180 then you will get the correct answer....try it and you will get the answer.I got that from my math teacher :)
360 degrees
180
720
360
360
35
180
The sum of the measures of the angles in a figure having 9 sides is 20 degrees each angle.
Sum= 2340 Degrees A+
1,080
supplementary
complement