A triangle’s side lengths are whole numbers. If the measure of two of its sides are 1 cm and 13 cm, what is the measure of the third side?(1 point)

Responses

1 cm
1 cm

12 cm
12 cm

13 cm
13 cm

12.5 cm

1 answer

To find the possible length of the third side of a triangle with side lengths of 1 cm and 13 cm, we can use the triangle inequality theorem:

  1. The sum of the lengths of any two sides must be greater than the length of the remaining side.

Given sides \( a = 1 \) cm and \( b = 13 \) cm, we can denote the third side as \( c \). The triangle inequality gives us the following conditions:

  1. \( a + b > c \)

    • \( 1 + 13 > c \)
    • \( 14 > c \)
    • Thus, \( c < 14 \)
  2. \( a + c > b \)

    • \( 1 + c > 13 \)
    • \( c > 12 \)
  3. \( b + c > a \)

    • \( 13 + c > 1 \)
    • This condition is always satisfied because \( c \) is a positive length.

From the inequalities derived, we have:

  • \( c < 14 \)
  • \( c > 12 \)

Combining these, we find that the only integer value that satisfies \( 12 < c < 14 \) is:

  • \( c = 13 \) cm

Therefore, the measure of the third side must be 13 cm.