To get the solution, we are looking for, we need to point out what we know. 
1. We assume, that the number 43.75 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 43.75, so we can write it down as 100%=43.75. 
4. We know, that x% equals 70 of the output value, so we can write it down as x%=70. 
5. Now we have two simple equations:
1) 100%=43.75
2) x%=70
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%=43.75/70
6. Now we just have to solve the simple equation, and we will get the solution we are looking for.
7. Solution for 70 is what percent of 43.75
100%/x%=43.75/70
(100/x)*x=(43.75/70)*x       - we multiply both sides of the equation by x
100=0.625*x       - we divide both sides of the equation by (0.625) to get x
100/0.625=x 
160=x 
x=160
now we have: 
70 is 160% of 43.75