PDF chapter test TRY NOW

A man-hole cover of a water sump is in square shape.
 
1. In how many ways we can fix that to close the sump?
 
2. What is its order of rotational symmetry?
 
YCIND_231201_5813_ex13.png
 
Answer:  
 
We can fix the sump in ways.
 
The  order of rotational symmetry is .