Cyndi has 20 square tiles to make rectangles. she uses all 20 tiles in each rectangle. how many different shaped rectangles can she make

I have an examp that i think will help
A rectangle made of square tiles measures 8 tiles wide and 10 tiles long. What is the length in tiles of a similar rectangle 12 tiles wide?
Scaling factor is 12/8 = 3/2 
Therefore length of the 12 tiles wide rectangle is 10 times 3/2 = 15 tiles long
Hope this helps

What am i doing here. add?