If a building casts a 100ft shadow while a 4'6'' tall pole cast a 3'4'' shadow, what is the height of the building with the 100ft shadow?
Set up the proportion: height/shadow = height/shadow
4'6" = 4.5' and 3'4" = 3.25'
---> x / 100 = 4.5 / 3.25
Cross-multiply:
---> 3.25x = 4.5·100
---> 3.25x = 450
---> x = 450 / 3.25
---> x = 138.5 feet (approx)