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
Light as a Feather
I'm light as a feather, yet the strongest man can't hold me for more than a few minutes.
What Am I?