A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 680 sq. feet, how many feet of fencing will be required ?  Choose one
A) 34  B) 40  C) 68  D) 88  E) None of these
Solution   We have : l = 20 ft and lb = 680 sq. ft. So, b = 34 ft.   ∴ Length of fencing = (l + 2b) = (20 + 68)= 
<gadget id="calculator">(20 + 68)</gadget>
<output>88</output>
88 ft. Answer 88
<result>D</result>
A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 680 sq. feet, how many feet of fencing will be required ?