Surface area of 3-dimensional shapes

Lessons

1. 
   
   
   1. What are the dimensions of the cutout piece?
   2. How does the surface area of the original rectangular object change after cutting out the corner piece?
2. Below is a rectangular object formed by six blocks which all have the same size.
   
   
   1. What are the dimensions of one block?
   2. What is the surface area of one block?
   3. Calculate the ratio of the surface area of the rectangular object to the total surface area of the six blocks.