Math Problem Statement

Which of the following sets of numbers could not represent the three sides of a triangle?

Solution

To determine which set of numbers could not represent the sides of a triangle, we need to apply the triangle inequality theorem. This theorem states that for any three sides to form a triangle, the sum of the lengths of any two sides must be greater than the length of the third side.

Let’s check each option:

  1. {7, 14, 18}:

    • 7+14=21>187 + 14 = 21 > 18
    • 7+18=25>147 + 18 = 25 > 14
    • 14+18=32>714 + 18 = 32 > 7
      This set satisfies the triangle inequality, so these can form a triangle.
  2. {7, 13, 22}:

    • 7+13=20227 + 13 = 20 \not> 22
      Since 20 is not greater than 22, this set does not satisfy the triangle inequality, so these cannot form a triangle.
  3. {7, 18, 23}:

    • 7+18=25>237 + 18 = 25 > 23
    • 7+23=30>187 + 23 = 30 > 18
    • 18+23=41>718 + 23 = 41 > 7
      This set satisfies the triangle inequality, so these can form a triangle.
  4. {14, 18, 30}:

    • 14+18=32>3014 + 18 = 32 > 30
    • 14+30=44>1814 + 30 = 44 > 18
    • 18+30=48>1418 + 30 = 48 > 14
      This set satisfies the triangle inequality, so these can form a triangle.

Conclusion:

The set {7, 13, 22} does not satisfy the triangle inequality theorem and cannot represent the sides of a triangle.

Would you like more details on how the triangle inequality works or have any other questions?


Here are 5 related questions to expand on this topic:

  1. How does the triangle inequality theorem relate to the Pythagorean theorem?
  2. Can a triangle have side lengths that are all equal? What type of triangle is this?
  3. What are the properties of a right triangle in relation to side lengths?
  4. How can you check if three sides form a valid triangle without calculating each inequality?
  5. How does the triangle inequality theorem apply to angles in a triangle?

Tip: The triangle inequality theorem is a quick way to check the feasibility of triangle formation just by comparing the side lengths without needing to draw the figure.

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Math Problem Analysis

Mathematical Concepts

Geometry
Triangle Inequality Theorem

Formulas

Sum of any two sides of a triangle must be greater than the third side

Theorems

Triangle Inequality Theorem

Suitable Grade Level

Grades 6-9