Answer:
Step-by-step explanation:
Twelve
You are correct, but I have a small comment.
As far as I can see, you have both 12 and 13 correct. The short way to do 12 is just to divide 72 into 360
360 / 72 = 5
The more general formula is 360 / central angle = # of sides.
What the question means is that if your start with a polygon (it is a regular polygon by the way), and rotate it around its center, how many sides does it have in order that when you go through 72 degrees, the figure looks like it did when you started.
If the polygon is completely unmarked, then the idea is that it will look like you haven't done anything to the polygon even though you have rotated it 72 degrees.
The way you did 13 is exactly how it should be done.
