Answer: 20 sides
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Work Shown:
x = exterior angle
9x = interior angle
interior + exterior = 180
9x+x = 180
10x = 180
x = 180/10
x = 18
n = number of sides
n = 360/x
n = 360/18
n = 20
There are 20 sides to the regular polygon.
Side notes:
- The formula to determine n only works for regular polygons.
- A polygon with 20 sides is known as an icosagon.
- Any pair of adjacent interior and exterior angles are supplementary. They add to 180 degrees.