Answer:
x = 5
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides, that is
x² + 9² = 16²
x² + 81 = 256 ( subtract 81 from both sides )
x² = 175 ( take the square root of both sides )
x = = 5
≈ 13.23 units ( to 2 dec. places )