The number of sides is the same as the number of lines of symmetry and the order of rotational symmetry.
So, a regular decagon would have 10 lines of symmetry.
Answer: C on edge
Step-by-step explanation:
A: .44 (not repeating)
b: also .444 (repeating)
c: .41666666667 (repeating, I think)
d: .875 (not repeating)