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.
Answer:
75
Step-by-step explanation:
The measure of two supplementary angles = 15:21
The angles are 15x , 21x
15x + 21x = 180 {Supplementary}
36x = 180
x = 180/36
x = 5
Smallest angle = 15 * 5 = 75
The possibilities are endless
If we're talking between 1-20
then the numbers divisible by 2 and 6 are
18,12,6
We know that they have:
2 entrences
3 ways to chose (escalator,elevator and stairs)
8 gates
and again 3 ways to chose (escalator, elevator and stairway)
now you have to multiply it:
There are 144 different ways that Anita and Terry can go from street level to the trains:)
