The schematic diagram below represents the path followed by the glider,
The point A represents the location of the airport.
Observe that the path of the glider forms a right angled triangle ABC.
So the hypotenuse AC can be calculated by using Pythagoras Theorem as,
[tex]\begin{gathered} AC^2=AB^2+BC^2 \\ AC^2=(8)^2+(15)^2 \\ AC^2=64+225 \\ AC^2=289 \\ AC^2=17^2 \\ AC=17 \end{gathered}[/tex]
Thus, the distance of the glider's last leg back to the airport is 17 miles.
So the second option is the correct choice.
