The solution for this problem is just simple. It tells you to find the area in square feet. Thus, convert the units to feet first. The conversion you need to know are: 12 in = 1 ft and 3 ft = 1 yard.
Width = 42 in * 1 ft/12 in = 3.5 ft Length = 10 yards * 3 ft/1 yard = 30 ft
Area = Length*Width = 30*3.5 <em>Area = 105 ft²</em>
