Answer:
AC = 4
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
AC² + 9² = 17²
AC² + 81 = 289 ( subtract 81 from both sides )
AC² = 208 ( take the square root of both sides )
AC =
= 4
← exact value
≈ 14.42 ( to 2 dec. places )