Two sides of a triangle are 6 cm and 11 cm. The third side is a whole number of centimetres. How many different lengths are possible for the third side?

Explanation

1. 01

   The third side must be greater than $11 - 6 = 5$ and less than $11 + 6 = 17$.

2. 02

   So it can be 6, 7, 8, …, 16 cm.

3. 03

   That is $16 - 6 + 1 = 11$ lengths.