whistle or horn AND a bell
40' * 20 ' = 800 sq feet = 74.3 metres2
Depends on the length of the trailer being pulled , can range anywhere from a 20 foot trailer to a 40foot trailer to an extenable one reaching 70 foot . Normal length is about 53 foot including the tractor unit .
What you have is this In the first measurment it is 8.444 sq. yards In the second measurment you have 11.851 sq. yards The difference being 3.407 sq.yards It will be 228 cubic feet to 320 cubic feet The difference of 92 cubic feet