Answer:
Jill's feet are 17 feet from the balloon.
Step-by-step explanation:
The situation is sketched in the figure attached.
The from the ground to the balloon, the distance from Jack to Jill, and the distance from the balloon to Jill's feet forms a right triangle.
The Pythagorean Theorem says the sum of the squares of the sides of the right triangle is equal to the square of its hypotenuse [tex]x[/tex]:
[tex](8ft)^2+ (15ft)^2 = x^2[/tex]
simplifying we get
[tex]64ft^2+225ft^2=x^2[/tex]
[tex]289ft^2= x^2[/tex],
and take the square root of both sides to get:
[tex]x = \sqrt{289ft^2}[/tex]
[tex]\boxed{x = 17ft.}[/tex]
Thus, Jill's feet are 17 feet from the balloon.