A rectangular field is to be fenced on three sides leaving a side of 20 feet uncovered. If the area of the field is 720sq. feet, how many feet of fencing will be required?  Choose the correct choice from the following answers:
A) 34 B) 92 C) 68 D) 88 E) None
EXPLANATION   We have: l = 20 ft and lb = 720 sq. ft.   So, b = 36 ft.   Length of fencing = (l + 2b) = (20 + 72)= 
<gadget id="calculator">(20 + 72)</gadget>
<output>92</output>
92 ft.   Answer 92
<result>B</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 720sq. feet, how many feet of fencing will be required?