What I did was:
4.5% is equal to 1.22, so the ratio is 4.5 to 1.22. 4.5% is equal to 4.5/100 so I did 100/4.5 and multiplied the outcome by 1.22 and got 27.11111111111(so on). So I believe the answer is the actual rocket is 27.11111111111(so on) mph high.