A rectangular field is to be fenced on three sides leaving a side of 10 feet uncovered. If the area of the field is 240 square feet, how many feet of fencing will be required?

Explanation: Let the sides of the rectangle be \(L\) and \(W\). Area \(A = L \times W = 240\) sq. ft. One side of 10 feet is left uncovered, so either \(L=10\) or \(W=10\). Assume \(W=10\) ft. Then \(L \times 10 = 240 \Rightarrow L = 24\) ft. The fencing covers three sides: the two sides of length \(L\) and the one side of length \(W\) that is covered (or vice versa). Required fencing length = \(L + W + L\) (if W is uncovered side) or \(W + L + W\) (if L is uncovered side). Since the uncovered side is 10 ft: Case 1: The side \(W=10\) is uncovered. Fencing length = \(L + L + W = 24 + 24 + 10 = 58\) ft. Case 2: The side \(L=24\) is uncovered. Fencing length = \(W + W + L = 10 + 10 + 24 = 44\) ft. The explanation calculation: \(24 + 10 + 24 = 58\) implies the side of 10 ft is one of the sides being covered, but the text says the 10 ft side is **uncovered**. If the uncovered side is 10 ft, the other side is \(240/10 = 24\) ft. The sides being fenced are: \(24 + 10 + 24 = 58\) (assuming the two longer sides and one shorter side are fenced). The correct interpretation based on the source's calculation and the available option is 58.