81 is what percent of 428 - 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 428 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 428, so we can write it down as 100%=428.
4. We know, that x% equals 81 of the output value, so we can write it down as x%=81.
5. Now we have two simple equations:
1) 100%=428
2) x%=81
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%=428/81
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 81 is what percent of 428

100%/x%=428/81
(100/x)*x=(428/81)*x       - we multiply both sides of the equation by x
100=5.283950617284*x       - we divide both sides of the equation by (5.283950617284) to get x
100/5.283950617284=x
18.92523364486=x
x=18.92523364486

now we have:
81 is 18.92523364486% of 428