0.81 is what percent of 12.9 - 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 12.9 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 12.9, so we can write it down as 100%=12.9.
4. We know, that x% equals 0.81 of the output value, so we can write it down as x%=0.81.
5. Now we have two simple equations:
1) 100%=12.9
2) x%=0.81
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%=12.9/0.81
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 0.81 is what percent of 12.9

100%/x%=12.9/0.81
(100/x)*x=(12.9/0.81)*x       - we multiply both sides of the equation by x
100=15.925925925926*x       - we divide both sides of the equation by (15.925925925926) to get x
100/15.925925925926=x
6.2790697674419=x
x=6.2790697674419

now we have:
0.81 is 6.2790697674419% of 12.9