39.78 is what percent of 255 - 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 255 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 255, so we can write it down as 100%=255.
4. We know, that x% equals 39.78 of the output value, so we can write it down as x%=39.78.
5. Now we have two simple equations:
1) 100%=255
2) x%=39.78
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%=255/39.78
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 39.78 is what percent of 255

100%/x%=255/39.78
(100/x)*x=(255/39.78)*x       - we multiply both sides of the equation by x
100=6.4102564102564*x       - we divide both sides of the equation by (6.4102564102564) to get x
100/6.4102564102564=x
15.6=x
x=15.6

now we have:
39.78 is 15.6% of 255