Since the expression x^2 -4 is the difference of two squares, it can be factored into the following terms:
(x-2)(x+2)
The expression 2x + 4 can be factored as:
2(x+2)
The ratio of the area to the leg would then be:
(x-2)(x+2)/ 2(x+2)
Then (x+2)/((x+2) is equivalent to one (or they cancel out), so the expression becomes:
(x-2)/2
So the ratio of the area to the leg is (x-2) / 2
 
     
             
 
                     
                    