how to draw those nonconstructive polygon with a pentagon

The pentagon is a good polygon which you can find lots of interesting staff. I had found some interesting points which can be used to setup those nonconstructive polygon very quickly.

The main idea is to draw a red line so you can get two points which can be used to create the central angel of those polygons.

To find other special points, the orange segment means to get midpoint of the whole segment. yellow segment means to get half of the half segment.

I list all those polygon that I drawed before. I found these quick method one month before I find the self accurate method.

I think it is interesting to do it so I post all these method.

The ping-pong method to constructe nonconconstructive polygon

I had post the self accurate method for most nonconstructive regular polygon which less than 25. the method can be remember easily by ping-pong. that is: start from one angel, if the angel is odd number, then find a bisector at another side(cross the center of the circle.);calculate the divided number, if the number is even, then bisector at same side,till the number is odd, if it is not 1, then continue, if it is 1,then stop. It is one circle. you can continue many circles if you want very accurate number.

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.

how to draw a perfect Icosikai-trigon

Icosikai-trigon is also the nonconstructive polygon.

with the method I post here in the picture, you can quickly set up a start angel which is 7 times of the central angel of the Icosikai-trigon.

The detail drawing process see my last post.

How to draw those nonconstructive polygon with super accuracy

To draw a polygon with a start up angel will create some error for those nonconstructive polygon. Even with a very accurate angel, you may not be able to draw this kind of polygon with any accuracy.

I had studied some days and found a self accurate method which can allow you to draw any accuracy with any start-up angel .

I post some picture to show how to do it.