21 is what percent of 1780 - 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 1780 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 1780, so we can write it down as 100%=1780.
4. We know, that x% equals 21 of the output value, so we can write it down as x%=21.
5. Now we have two simple equations:
1) 100%=1780
2) x%=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%=1780/21
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.

7. Solution for 21 is what percent of 1780

100%/x%=1780/21
(100/x)*x=(1780/21)*x       - we multiply both sides of the equation by x
100=84.761904761905*x       - we divide both sides of the equation by (84.761904761905) to get x
100/84.761904761905=x
1.1797752808989=x
x=1.1797752808989

now we have:
21 is 1.1797752808989% of 1780