# geometry

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what is the formula for the area of a regular polygon?

• geometry -

A =(1/4) n a^2 ctn (180/n)
A is area
a is length of side
n is number of sides
ctn is cotangent

• geometry -

if the angle of a regular polygon is 20 degrees how many sides does the ploygon have? 18 sides, but show your work

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