The sum of angles in a regular n sided polygon:
(n - 2)*180
(n - 2)*180 = 11520
(n - 2) = 11520/180
(n - 2) = 64
n - 2 = 64
n = 64 + 2
n = 66
Polygon has 66 sides.
There is 180 degrees in a triangle so it is 80 degrees
<span>There is not a property of "1" for addition, but the identity property in this case uses "0" instead. If a number is increased by 1, the value will necessary be increased or decreased by the amount added or subtracted. However, if the number either adds or subtracts zero, then value will be left unchanged. Examples: 3+1 = 4, but 3+0 = 3,</span>
