How to draw a perfect Icosikai-pentagon with compass and straight

Icosikai-pentagon is nonconstructive polygon by compass and straight.

But with the method I post in the picture,one can draw a nearly perfect Icosikai-pentagon with compass and straight.

the first step is to construct a angel which is 9 times of the central angel of the Icosikai-pentagon. the method I found now has little error which make one can use compass and straight drawing perfectly.

it is possible to draw the Icosikai-pentagon with any wanted accuracy. the details post on the previous article.