643.5 is what percent of 850 - 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 850 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 850, so we can write it down as 100%=850.
4. We know, that x% equals 643.5 of the output value, so we can write it down as x%=643.5.
5. Now we have two simple equations:
1) 100%=850
2) x%=643.5
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%=850/643.5
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 643.5 is what percent of 850

100%/x%=850/643.5
(100/x)*x=(850/643.5)*x       - we multiply both sides of the equation by x
100=1.3209013209013*x       - we divide both sides of the equation by (1.3209013209013) to get x
100/1.3209013209013=x
75.705882352941=x
x=75.705882352941

now we have:
643.5 is 75.705882352941% of 850