Ask Me Help Desk - 72% of what number is 648

To solve this you set up an equation. You have an unknown number, call it "X", and you know that 72% of X is equal to 648. Taking 72% of something is like multiplying it by 0.72, so you have:

$ 0.72 \times X = 648 $

Now you can divide both sides by 0.72:
$ \frac {0.72 \times X } {0.72} = \frac {648} {0.72} \\ \frac {\cancel{0.72} \times X } {\cancel{0.72}} = \frac {648} {0.72} \\ X = \frac {648} {0.72} $

Can you take it from here?