17.28 is what percent of 90 - step by step solution

To get the solution, we are looking for, we need to point out what we know.

1. We assume, that the number 90 is 100% - because it's the output value of the task.
2. We assume, that x is the value we are looking for.
3. If 100% equals 90, so we can write it down as 100%=90.
4. We know, that x% equals 17.28 of the output value, so we can write it down as x%=17.28.
5. Now we have two simple equations:
1) 100%=90
2) x%=17.28
where left sides of both of them have the same units, and both right sides have the same units, so we can do something like that:
100%/x%=90/17.28
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 17.28 is what percent of 90

100%/x%=90/17.28
(100/x)*x=(90/17.28)*x       - we multiply both sides of the equation by x
100=5.2083333333333*x       - we divide both sides of the equation by (5.2083333333333) to get x
100/5.2083333333333=x
19.2=x
x=19.2

now we have:
17.28 is 19.2% of 90