1.21 is what percent of 3.99 - 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 3.99 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 3.99, so we can write it down as 100%=3.99.
4. We know, that x% equals 1.21 of the output value, so we can write it down as x%=1.21.
5. Now we have two simple equations:
1) 100%=3.99
2) x%=1.21
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%=3.99/1.21
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 1.21 is what percent of 3.99

100%/x%=3.99/1.21
(100/x)*x=(3.99/1.21)*x       - we multiply both sides of the equation by x
100=3.297520661157*x       - we divide both sides of the equation by (3.297520661157) to get x
100/3.297520661157=x
30.325814536341=x
x=30.325814536341

now we have:
1.21 is 30.325814536341% of 3.99