7.8 is what percent of 90 - 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 90 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 90, so we can write it down as 100%=90.
4. We know, that x% equals 7.8 of the output value, so we can write it down as x%=7.8.
5. Now we have two simple equations:
1) 100%=90
2) x%=7.8
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%=90/7.8
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 7.8 is what percent of 90

100%/x%=90/7.8
(100/x)*x=(90/7.8)*x       - we multiply both sides of the equation by x
100=11.538461538462*x       - we divide both sides of the equation by (11.538461538462) to get x
100/11.538461538462=x
8.6666666666667=x
x=8.6666666666667

now we have:
7.8 is 8.6666666666667% of 90