Question

ABCDEFGH is a regular octagon. The minimum degree of rotation by which this octagon can map onto itself is °. It will take increments of that degree of clockwise rotation for A′ (the image of A) to coincide with C

Answer 1

We need the diagram

But it should be evident:

If it is a regular octagon what is the angle between vertices?

If you rotate the figure by that amount then oyu can see that it 'maps to itself' i.e. you cannot tell the difference between the original and rotated figure.

Each time you rotate by that amount the figure appears teh same.

When oyu look at your diagram - how many times do you need to do this until A would be in the position of C??