How many triangles can you make with the given lengths of three line segments are 4 centimeters, 5 centimeters, and 9 centimeters.

None.  The triangle inequality states that the sum of the smaller two sides of a triangle must be greater than the third side.  As 4+5=9, this inequality is false in this case, so these sides cannot create a triangle. 

The right answer should be 6 but your not very specific