Question 735742
One ratio is given:  1 bag = 400 yd^2; but the lawn measurements are in feet.  Decide if you want to do calculations using yards or in feet. That is YOUR choice.  Another ratio needed is 3 feet = 1 yard.


Start from lawn area and use a chain of ratios to find how many bags of fertilizer.  Here is maybe the most direct way to go:


{{{highlight((120Feet*360Feet)*(1Yard/3Feet)*(1Yard/3Feet)*(1Bag/(400Yard^2))=12)}}} Bags


Check how the units work.  The ratios need to be used so that the units work correctly.