Cut a rectangular Cake

Problem

How do you cut a rectangular cake into two equal pieces when someone has already taken a rectangular piece from it?
The removed piece an be any size or at any place in the cake. You are only allowed one straight cut. 

 

Solution

Join the centers of the original and the removed rectangle. It works for cuboids too!

References

• http://sudhansu-codezone.blogspot.in/2011/12/cut-rectangular-cake.html