A rectangular field has 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 the correct choice from the following.
A) 80 feet	B) 85 feet	C) 83 feet	D) 88 feet	E) 90 feet
Given that area of the field = 680 sq. feet   =&gt; lb = 680 sq. feet   Length(l) = 20 feet   =&gt; 20 × b = 680   =&gt; b = 680/20= 
<gadget id="calculator">680/20</gadget>
<output>34</output>
34 feet   Required length of the fencing= l + 2b = 20 + (2 × 34) = 88 feet   Answer is 88 feet.
<result>D</result>
A rectangular field has 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?