We assume, that the number 320 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 320 is 100%, so we can write it down as 320=100%. 4. We know, that x is 45% of the output value, so we can write it down as x=45%. 5. Now we have two simple equations: 1) 320=100% 2) x=45% 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: 320/x=100%/45% 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 45% of 320
320/x=100/45 (320/x)x=(100/45)x - we multiply both sides of the equation by x 320=2.22222222222*x - we divide both sides of the equation by (2.22222222222) to get x 320/2.22222222222=x 144=x x=144
