128.4 is what percent of 139 - 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 139 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 139, so we can write it down as 100%=139.
4. We know, that x% equals 128.4 of the output value, so we can write it down as x%=128.4.
5. Now we have two simple equations:
1) 100%=139
2) x%=128.4
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%=139/128.4
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 128.4 is what percent of 139

100%/x%=139/128.4
(100/x)*x=(139/128.4)*x       - we multiply both sides of the equation by x
100=1.082554517134*x       - we divide both sides of the equation by (1.082554517134) to get x
100/1.082554517134=x
92.374100719424=x
x=92.374100719424

now we have:
128.4 is 92.374100719424% of 139