If the sum of the lengths of any two sides of a triangle is less than or equal to the length of the third side, then the triangle is not possible.
Step-by-step explanation:
If a triangle has sides with lengths of 8, 9, and 18, notice that 8 +9 or 17 is NOT greater than 18. So the sum of the lengths of two sides of the triangle is less than the length of the third side.
Therefore the triangle with sides of lengths
is NOT possible
