Sarah has toothpicks that are 4 different lengths, 3 in, 8in, 10in, 11in. She is trying to make as many triangles as she can

1 answer

To determine whether Sarah can make a triangle with combinations of toothpicks of different lengths, we can use the triangle inequality theorem. According to this theorem, for any triangle with side lengths \( a \), \( b \), and \( c \), the following must hold true:

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

Given the toothpick lengths: 3 inches, 8 inches, 10 inches, and 11 inches, we can check combinations of 3 lengths at a time to see if they can form a triangle.

Let's evaluate all the combinations:

  1. 3, 8, 10:

    • \( 3 + 8 = 11 \) (not > 10)
    • This combination cannot form a triangle.
  2. 3, 8, 11:

    • \( 3 + 8 = 11 \) (not > 11)
    • This combination cannot form a triangle.
  3. 3, 10, 11:

    • \( 3 + 10 = 13 > 11 \) (holds)
    • \( 3 + 11 = 14 > 10 \) (holds)
    • \( 10 + 11 = 21 > 3 \) (holds)
    • This combination can form a triangle.
  4. 8, 10, 11:

    • \( 8 + 10 = 18 > 11 \) (holds)
    • \( 8 + 11 = 19 > 10 \) (holds)
    • \( 10 + 11 = 21 > 8 \) (holds)
    • This combination can form a triangle.

So, based on the evaluations:

  • The valid combinations that can form triangles are (3, 10, 11) and (8, 10, 11).
  • Hence, Sarah can make 2 triangles with the toothpicks of given lengths.