geometry
posted by
JdS
.
what is the formula for the area of a regular polygon?

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