Equilateral triangle T has a perimeter that is one-third the perimeter of equilateral triangle S. If one side of triangle S is 9 inches long, what is the length, in inches, of one side of triangle T?

Answer: A. 3

Explanation: Since triangle S is equilateral and has a side length of 9 inches, its total perimeter is 9 × 3 = 27 inches. The perimeter of triangle T is one-third of that, which equals 9 inches (27 ÷ 3). Because triangle T is also equilateral, divide its total perimeter by its 3 equal sides to find the individual side length: 9 ÷ 3 = 3 inches.

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