Question

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Answer 1

a)
There are \((n-2)180\) degrees in a polygon with n sides. This is because you can fit n-2 triangles in an n-sided polygon. For example, a triangle as three sides so, of course, you can fit a triangle inside a triangle.
b)
So if there are \((n-2)180\) degrees in a polygon with n sides, then each angle is simply this number divided by n: \((180-360/n)\).
c)
Tracing all the way around the polygon makes one full turn, so the sum of the exterior angles must be 360°.
d)
The exterior angle is the supplementary angle to the interior angle. so subtract from 180 what you got in b
e)
Obvious based on definition of supplementary angle - http://en.wikipedia.org/wiki/Polygon#Angles

Answer 2

Thank you so much!