Since 3/4 foot is less than 1 foot ,what unit can you use to show 3/4 is 3/4 of 12 inches

3/4  =  9/12   

You know you have 4 and 12 as your denominators.  4 x ? = 12

It's 3.  4 x 3 = 12  what you do to the bottom you do to the top, you multiplied x' 3

3 x 3 = 9

4 x 3 = 12

So, 3/4 is equal to 9/12

or 9 inches of 12 inches is equal to 3/4 of a foot.

Hope this helps. :)

good luck!

cutie~