Q is in 2x2 matrix form, Q= (0, -1, 1, 0)

Using geometrical reasoning only, state the smallest possible values of k given that:

a)Q^-1=Q^k

Q^-1=Q^3

b) Q^5=Q^k

Q^%=Q^1

c) Q^2=Q^k

Q^-2=Q^2

See, I know how to get the answer, I just don't know how to explain it using geometrical reasoning.