The length of a rectangle is three times longer than its width. The perimeter of the rectangle is 16 feet. If x represents the width of the rectangle in feet, which equation can be used to find its value?

The width is x feet, so the length is 3x feet. A rectangle’s perimeter is the sum of all four sides: 3x + 3x + x + x. Setting that sum equal to 16 gives 3x + 3x + x + x = 16, which is choice C.

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