What is 4 percent of 640.57 - 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 640.57 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 640.57 is 100%, so we can write it down as 640.57=100%.
4. We know, that x is 4% of the output value, so we can write it down as x=4%.
5. Now we have two simple equations:
1) 640.57=100%
2) x=4%
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:
640.57/x=100%/4%
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 4% of 640.57

640.57/x=100/4
(640.57/x)*x=(100/4)*x       - we multiply both sides of the equation by x
640.57=25*x       - we divide both sides of the equation by (25) to get x
640.57/25=x
25.6228=x
x=25.6228

now we have:
4% of 640.57=25.6228