Since we know that triangle inequality theorem states that sum of any two sides of a triangle must be greater than third side.
Now let us see if it is true for our given side lengths.


Now let us try with another pair.


We can see that sum of 5.6 and 4 is less than 10.6. Therefore, 10.6 cm, 5.6 cm and 4.0 cm can not be side lengths of a triangle.