To form a triangle, the sum of any two sides must be greater than the remaining side. For the sides of 4cm, 5cm and 9cm, the sum of the 4cm and 5cm sides is 9cm, which is greater than the remaining 9cm side. Therefore, these lengths can form a triangle because they satisfy the triangle inequality condition that the sum of any two sides must be greater than the third side.

1. Question
Can sides with
4cm, 5 cm and 9
cm form a
triangle?
What are the
conditions to
construct a
triangle?

2. Triangle Inequality
Theorem