When we rotate a figure and there is no change in the shape of the figure then it has rotational symmetry.
We know that the order of rotation for a square is 4.
Hence, we have 
Thus, the angle of rotational symmetry of square are

Hence, the minimum angle of rotational symmetry is 
Therefore, the minimum angle of rotational symmetry for a square is 90 degrees.
Step-by-step explanation:

The product of a rational number multiplied by itself is called as a perfect square.,we can easily find out the square root for a number which is a imperfect square
Step-by-step explanation:
using the following formula we can find a square root for a number which is a imperfect square
X = Non perfect square
√x = (square root of nearest lower perfect square +(x - perfect square)÷2×(√perfect square )
Example
√38
the nearest perfect root is 36
36 (√36=6)
so √38 = √36 + (38-36)/2√36
= 6 + 2/12
=6 + 1/6 = 6.166 (answer)

I think it’s either C or D