Here, we want to select which of the lengths could not be that of a right triangle
For a set of three numbers to be the sides of a right triangle
They must obey the Pythagoras' theorem
With respect to the question, we can have it restated that the square of the biggest numbers equal the sum of the squares of the two smaller ones
This brings us to the concept of Pythagorean triple
These are three numbers that at any time will form the sides of a right triangle
The correct answer in this case is the first one because the square of 16 is not equal to the sum of the squares of 10 and 4
All other options have the square of the biggest side equal to the sum of the squares of the two smaller ones