3.9 is what percent of 31.4 - 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 31.4 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 31.4, so we can write it down as 100%=31.4.
4. We know, that x% equals 3.9 of the output value, so we can write it down as x%=3.9.
5. Now we have two simple equations:
1) 100%=31.4
2) x%=3.9
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%=31.4/3.9
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 3.9 is what percent of 31.4

100%/x%=31.4/3.9
(100/x)*x=(31.4/3.9)*x       - we multiply both sides of the equation by x
100=8.0512820512821*x       - we divide both sides of the equation by (8.0512820512821) to get x
100/8.0512820512821=x
12.420382165605=x
x=12.420382165605

now we have:
3.9 is 12.420382165605% of 31.4