Can the sides of a triangle have lengths 5, 1, and 4?

1 answer

To determine whether three lengths can form a triangle, we can use the triangle inequality theorem. This theorem states that for any triangle with side lengths \(a\), \(b\), and \(c\), the following conditions must be satisfied:

  1. \(a + b > c\)
  2. \(a + c > b\)
  3. \(b + c > a\)

Given the lengths 5, 1, and 4, we can let \(a = 5\), \(b = 1\), and \(c = 4\). Now, we will check each of the triangle inequality conditions:

  1. \(a + b > c\) \[ 5 + 1 > 4 \quad \text{(6 > 4, which is true)} \]

  2. \(a + c > b\) \[ 5 + 4 > 1 \quad \text{(9 > 1, which is true)} \]

  3. \(b + c > a\) \[ 1 + 4 > 5 \quad \text{(5 > 5, which is false)} \]

Since the third condition (\(b + c > a\)) is not satisfied, the lengths 5, 1, and 4 cannot form a triangle. Thus, the answer is no.