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A triangle has a perimeter 13. The two shorter side, have integer lengths equal to x and x + 1. Which of the following could be the length of the other side.

  1. A) 2
  2. B) 6
  3. C) 8
  4. D) None
Show answer

Answer: B) 6

Explanation

B) 6. Let the third, longest side be y. Then 2x + 1 + y = 13, so y = 12 − 2x. The two shorter sides must add to more than y: 2x + 1 > 12 − 2x, so x ≥ 3. For y to be the longest, 12 − 2x ≥ x + 1, so x ≤ 3. Hence x = 3 and the sides are 3, 4 and 6.

Asked in: BAPEX 2017

Topic: Geometry and Mensuration