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

5.5
5.5

4.5
4.5

4.2
4.2

3.5
3.5

1 answer

To determine a possible measure for the third side of a triangle given the two sides (3.7 and 8.2), we 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's denote the lengths of the two known sides as \( a = 3.7 \) and \( b = 8.2 \), and the unknown third side as \( c \).

According to the Triangle Inequality Theorem, we have the following conditions:

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

Now, we will derive the inequalities for \( c \):

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

The first two inequalities give us the most relevant information about \( c \):

  • \( c < 11.9 \)
  • \( c > 4.5 \)

Combining these inequalities means:

\[ 4.5 < c < 11.9 \]

Therefore, the possible lengths for \( c \) must be greater than 4.5. Among the provided responses, the only value that satisfies this inequality is:

5.5

So the correct response is 5.5.