Brad, Jamie, and Iris were attempting to predict which straw lengths would create a triangle. The straws they are using are number 1 - 5 (shown in the picture) and their lengths are labeled in centimeters. Which student did NOT predict correctly?

1 answer

We need to check whether each student's prediction follows the triangle inequality theorem, which states that the sum of the lengths of any two sides of a triangle must be greater than the length of the remaining side.

Checking each student's predictions:

- Brad predicted that straws 2, 3, and 4 would create a triangle. This is correct, because for any two of those straws, the sum of their lengths is greater than the length of the remaining straw.
- Jamie predicted that straws 1, 3, and 4 would create a triangle. This is correct, because for any two of those straws, the sum of their lengths is greater than the length of the remaining straw.
- Iris predicted that straws 1, 2, and 5 would create a triangle. This is incorrect, because the sum of the lengths of straws 1 and 2 is equal to the length of straw 5, so they cannot form a triangle.

Therefore, Iris did NOT predict correctly.