What is 9 percent of 4.2 - 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 4.2 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 4.2 is 100%, so we can write it down as 4.2=100%.
4. We know, that x is 9% of the output value, so we can write it down as x=9%.
5. Now we have two simple equations:
1) 4.2=100%
2) x=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:
4.2/x=100%/9%
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for what is 9% of 4.2

4.2/x=100/9
(4.2/x)*x=(100/9)*x       - we multiply both sides of the equation by x
4.2=11.111111111111*x       - we divide both sides of the equation by (11.111111111111) to get x
4.2/11.111111111111=x
0.378=x
x=0.378

now we have:
9% of 4.2=0.378