Answer:
C
Step-by-step explanation:
There is a right triangle formed by the slant height, h and the radius
Use Pythagoras' theorem to solve for h
With radius = 8 ft ( half the diameter ) , slant height is hypotenuse
h² = 17² - 8² = 289 - 64 = 225
Take the square root of both sides
h = 
= 15 → C
