Answer:
It is not a right triangle
Step-by-step explanation:
A triangle has side lengths of 8 inches, 12 inches, and 16 inches.
To determine if it is a Right Triangle, we make use of the Pythagoras Theorem, i.e.

Now the Hypotenuse is always the longest side

The equality above is not true and in fact

Therefore the 3 numbers do not satisfy Pythagoras theorem and cannot be the lengths of a right triangle.