Fencing three sides of a rectangle:\nA rectangular field has one 20 ft side left unfenced. If the area is 680 sq. ft, how many feet of fencing are required for the other three sides?

Introduction / Context:
We know the area and that one side of 20 ft is open (no fence). Using area, we can find the other dimension; then the fencing equals the sum of the remaining three sides.

Given Data / Assumptions:

• One side (length) = 20 ft (unfenced).
• Area = 680 sq. ft ⇒ 20 × width = 680.
• Fencing needed = the other 20 ft side + both widths.

Concept / Approach:
Compute width from area, then sum three sides (20 + width + width). Avoid mixing up which side is open; the open side is specifically the 20 ft side.

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