Question

The lengths of three line segments are 4 centimeters, 5 centimeters, and 9 centimeters. Using this information, triangles can be constructed.

Answer 1

Well yes, one triangle can be constructed, but you wouldn't recognize it.
One of its angles is 180 degrees and the other two are both zero degrees.

Anybody who looks at it would think it's just a straight line segment, 9 cm long.