81 is what percent of 0.9 - 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 0.9 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 0.9, so we can write it down as 100%=0.9.
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%=0.9
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%=0.9/81
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 0.9

100%/x%=0.9/81
(100/x)*x=(0.9/81)*x       - we multiply both sides of the equation by x
100=0.011111111111111*x       - we divide both sides of the equation by (0.011111111111111) to get x
100/0.011111111111111=x
9000=x
x=9000

now we have:
81 is 9000% of 0.9