Question

Given cross shaped object can be rotated times during a full rotation of ${360}^{\text{o}}$ to make it look similar as its original shape.

Answer 1

We can see that cross-shaped object can rotate by ${90}^{\text{o}}$ four times during a full rotation of ${360}^{\text{o}}$ to make it look similar as its original shape.
An object possess rotational symmetry if it retains same shape as it was before rotation more than once during a full rotation.