Rotating rectangles

This task is about the cente of rotation and rotating a shape about a point.

Rectangle ABCD has been rotated clockwise to form the rectangle DEFG.
 

a) Which point is the centre of rotation? __________
 
b)
 
Through how many degrees has the rectangle been rotated? __________
 
c)
 
Rotate rectangle DEFG 180° clockwise about point P.
Draw the rectangle and label it D'E'F'G' respectively.