Question:

What is the number of distinct triangles with integral valued sides and perimeter 14?

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Order the sides as \(a \le b \le c\). The triangle inequality with perimeter 14 forces the longest side \(c\) to be less than 7.
Updated On: Nov 4, 2026
  • 6
  • 5
  • 4
  • 3
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The Correct Option is C

Solution and Explanation

Step 1: Set up the condition.
Let the sides be integers \(a \le b \le c\) with \(a+b+c=14\). A triangle exists only if \(a+b>c\), i.e. \(14-c>c\), so \(c<7\), i.e. \(c \le 6\). Also \(c \ge 5\) because \(3c \ge 14\).

Step 2: Enumerate by the longest side.
\(c=6\): \(a+b=8\) with \(a \le b \le 6\): \((2,6),(3,5),(4,4)\), so 3 triangles.
\(c=5\): \(a+b=9\) with \(a \le b \le 5\): \((4,5)\), so 1 triangle.
\(c=4\): \(a+b=10\) with \(b \le 4\) is impossible.

Step 3: Total.
The triangles are \((2,6,6),(3,5,6),(4,4,6),(4,5,5)\), a total of 4.

Final Answer:
The correct option is (3): 4
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