The first crane is 14 percent taller because if 200 + 200x = 228 then x=.14
The second crane is 20 percent taller because if 100 + 100x = 120 then x = .2
The third crane is 5 percent taller because if 140 + 140x = 147 then x = .5
The total percent is 39 because 14 + 20 + 5 = <<14+20+5=39>>39
The average percent greater the height of the crane is than the building is 13 because 39 / 3 = <<39/3=13>>13
#### 13