Hello!
To find the slant height you use the equation
a^2 + b^2 = c^2
a is radius
b is height
c is slant height
Put in the values you know
9^2 + 17^2 = c^2
square the numbers
81 + 289 = c^2
Add
370 = c^2
Take the square root of the number
19.2 = c
The answer is B)19m
Hope this helps!