81 is what percent of 309 - 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 309 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 309, so we can write it down as 100%=309.
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%=309
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%=309/81
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 309

100%/x%=309/81
(100/x)*x=(309/81)*x       - we multiply both sides of the equation by x
100=3.8148148148148*x       - we divide both sides of the equation by (3.8148148148148) to get x
100/3.8148148148148=x
26.21359223301=x
x=26.21359223301

now we have:
81 is 26.21359223301% of 309