This is the concept of linear scale factor: The length of the farmer shadow will be calculated as follows: (height of farmer)/(length of farmer shadow)=(height of the silo)/(length of silo shadow) let the length of farmer shadow be x height of farmer=72 inches= 6 ft length of silo shadow=31.5 ft height of silo=140 ft therefore plugging the above in the equation we get: 6/x=140/31.5 solving for x we get x/6=31.5/140 x=31.5/140×6 x=1.35 ft The length of the farmer shadow is 1.35 ft