Given 2 sides of a triangle, find a range of possible lengths for the third side

9yd, 32yd

1 answer

To find the range of possible lengths for the third side of a triangle when two sides are known, you can use the triangle inequality theorem. This theorem states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

Let the lengths of the two known sides be \(a = 9\) yards and \(b = 32\) yards, and let \(c\) be the length of the third side. According to the triangle inequality, we have the following three inequalities:

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

Now, substituting the values \(a = 9\) and \(b = 32\) into these inequalities:

  1. \(9 + 32 > c\)

    • \(41 > c\)
    • Therefore, \(c < 41\)
  2. \(9 + c > 32\)

    • \(c > 32 - 9\)
    • \(c > 23\)
  3. \(32 + c > 9\) (This inequality will always hold true since \(c\) must be positive.)

Combining the results from the first two inequalities, we get:

\[ 23 < c < 41 \]

Thus, the range of possible lengths for the third side \(c\) is:

\[ c \text{ must be greater than } 23 \text{ yards and less than } 41 \text{ yards.} \]