87 is what percent of 398 - 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 398 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 398, so we can write it down as 100%=398.
4. We know, that x% equals 87 of the output value, so we can write it down as x%=87.
5. Now we have two simple equations:
1) 100%=398
2) x%=87
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%=398/87
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 87 is what percent of 398

100%/x%=398/87
(100/x)*x=(398/87)*x       - we multiply both sides of the equation by x
100=4.5747126436782*x       - we divide both sides of the equation by (4.5747126436782) to get x
100/4.5747126436782=x
21.859296482412=x
x=21.859296482412

now we have:
87 is 21.859296482412% of 398