The hexagon gikmpr and triangle fjn are regular. the dashed line segments form 30 degrees angles.
what is the image of on after a rotation of 180?

Comment
When you go through 180 degrees, what happens is that you follow a straight line until you hit something on the other side of the line.

For example 

A ∨B

If you start at A and go through ∨ and onward to B, you have effectively gone through a rotation of 180o. 

Just to nail it down, in a rotation through 90° you would travel through a right angle like this one. ⊥ You would start on one of the horizontal ends and when you hit the vertical line you would go up 90° from where you started. If you go clockwise, N would be where R is for 90°.

Answer
You don't want 90 you want 180. I've just done that to explain it a little better.

NO would become OH <<<<<< answer.