Ok, so the first thing you need is how much taller the second model is than the first model the way we do that is we take the second model height and divide that by the first model height 120/1.8=66.667 or 66 2/3 Second now we need to multiply the length of the middle finger by 66.667 6*66.667=400 cm now we just need to convert 400 cm to meters and since there are 100 cm in a meter we can do this 400/100=4 me so the answer is the little finger needs to be 4 meters long.