A rectangular field is to be fenced on three sides leaving a side of 30 feet uncovered. If the area of the field is 810 sq. feet, how many feet of fencing will be required?
Choose the correct choice:	A) 34	B) 40	C) 68	D) 84	E) None
EXPLANATION   We have: l = 30 ft and lb = 810 sq. ft.   So, b = 27 ft.   Length of fencing = (l + 2b) = (30 + 54)= 
<gadget id="calculator">(30 + 54)</gadget>
<output>84</output>
84 ft.   Answer 84
<result>D</result>
A rectangular field is to be fenced on three sides leaving a side of 30 feet uncovered. If the area of the field is 810 sq. feet, how many feet of fencing will be required?