128.9 is what percent of 142 - 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 142 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 142, so we can write it down as 100%=142.
4. We know, that x% equals 128.9 of the output value, so we can write it down as x%=128.9.
5. Now we have two simple equations:
1) 100%=142
2) x%=128.9
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%=142/128.9
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 128.9 is what percent of 142

100%/x%=142/128.9
(100/x)*x=(142/128.9)*x       - we multiply both sides of the equation by x
100=1.1016291698991*x       - we divide both sides of the equation by (1.1016291698991) to get x
100/1.1016291698991=x
90.774647887324=x
x=90.774647887324

now we have:
128.9 is 90.774647887324% of 142