We assume, that x is the value we are looking for.
If 100% equals to 170, so we can write it down as 100%=170
we know that x% equals 63 of the output value, so we can write it down as x%=63.
Now we have two simple equations:
100%=170
x%=63
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%=170/63
Now we just have to solve the simple equation, and we will get the solution we are looking for.
Which equals x=37.0588235294
So if we rounded that it would be 37.
