Here we have to use the sum of angles of a polygon formula which is
S=(n-2)180
Here S=360 and n is unknown, so on substituting the value of S, we will get
360 = (n-2)180
Dividing both sides by 180
2 = n -2
Adding 2 to both sides
n=4
So it must be a quadrilateral with all equal sides. But each angle is 90 degree. THerefore the polygon is a square .
