1. We assume, that the number 200 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 200 is 100%, so we can write it down as 200=100%.
4. We know, that x is 28% of the output value, so we can write it down as x=28%.
5. Now we have two simple equations:
1) 200=100%
2) x=28%
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:
200/x=100%/28%
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 28% of 200
x=56
so now we have:
28% of 200=56