If we look at the green bar we see that its real height is 2/3 of its shadow. So that means we need to find 2 shadows length for the red bar, the uninterruped part and the one on the wall. Since we now know the formula for the floor shadow - real height is 2/3 of it - meaning the part that makes that shadow is 4 meters long. Then we have to add the part on the wall which is straight up, it has no formula so we just add those 4 meters on the wall to the 4 meters we got from multiplying 2/3 by 6 meters and we have 4 meters + 4 meters = 8 meterss
From Head to Toes
You use me from your head to your toes. The more I work, the thinner I grow. What am I?