Two sides of a triangle measure 3.7 and 8.2. Apply the Triangle Inequality Theorem to find a possible measure of the third side.(1 point)

Responses

3.5
3.5

4.5
4.5

4.2
4.2

5.5
5.5

1 answer

The Triangle Inequality Theorem states that for any triangle with sides of lengths \(a\), \(b\), and \(c\), the following inequalities must hold:

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

Given two sides of the triangle, 3.7 and 8.2, let's denote them as \(a = 3.7\) and \(b = 8.2\). We can find a range of possible values for the third side \(c\) using the triangle inequality:

  1. From \(a + b > c\): \[ 3.7 + 8.2 > c \implies 11.9 > c \implies c < 11.9 \]

  2. From \(a + c > b\): \[ 3.7 + c > 8.2 \implies c > 8.2 - 3.7 \implies c > 4.5 \]

  3. From \(b + c > a\): \[ 8.2 + c > 3.7 \implies c > 3.7 - 8.2 \implies c > -4.5 \quad \text{(this inequality does not constrain \(c\))} \]

Combining the relevant inequalities, we find that: \[ 4.5 < c < 11.9 \]

Now, let's examine the provided options for possible measures of the third side:

  • 3.5: does not satisfy \(c > 4.5\).
  • 4.5: does not satisfy \(c > 4.5\) (it is equal, not greater).
  • 4.2: does not satisfy \(c > 4.5\).
  • 5.5: satisfies \(4.5 < c < 11.9\).

Therefore, the only valid possible measure of the third side is 5.5.