Classify each triangle as acute, right, or obtuse

6, 2sqrt55, 17

1 answer

To classify the triangle with sides 6, \(2\sqrt{55}\), and 17, we can use the triangle inequality theorem and the relationship between the lengths of the sides to determine whether the triangle is acute, right, or obtuse.

  1. Check if it's a valid triangle:

    • The sum of the lengths of any two sides should be greater than the length of the third side:

      • \(6 + 2\sqrt{55} > 17\)
      • \(6 + 17 > 2\sqrt{55}\)
      • \(2\sqrt{55} + 17 > 6\)
    • Calculate \(2\sqrt{55} \approx 2 \times 7.416 = 14.832\) (since \(\sqrt{55} \approx 7.416\))

    • \(6 + 14.832 \approx 20.832 > 17\) (holds true)

    • \(6 + 17 = 23 > 14.832\) (holds true)

    • \(14.832 + 17 \approx 31.832 > 6\) (holds true)

    Since all inequalities hold, it is a valid triangle.

  2. Classify the triangle:

    • We can use the relationship \(a^2 + b^2\) compared to \(c^2\) (where \(c\) is the longest side):

      • Let \(a = 6\), \(b = 2\sqrt{55}\), \(c = 17\).
      • Calculate \(a^2 + b^2\) and \(c^2\):
        • \(a^2 = 6^2 = 36\)
        • \(b^2 = (2\sqrt{55})^2 = 4 \times 55 = 220\)
        • \(c^2 = 17^2 = 289\)
    • Now, compute \(a^2 + b^2\):

      • \(a^2 + b^2 = 36 + 220 = 256\)
    • Compare \(a^2 + b^2\) with \(c^2\):

      • We find \(256 < 289\).
  3. Conclusion:

    • Since \(a^2 + b^2 < c^2\), the triangle is classified as obtuse.

Thus, the triangle with sides 6, \(2\sqrt{55}\), and 17 is an obtuse triangle.