let us represent the question with a diagram for better understanding.
Using Pythagoras theorem
![\begin{gathered} c^2=12^2+9^2 \\ c^2=144+81 \\ c=\sqrt[\square]{225} \\ c=15\text{ km} \end{gathered}](https://tex.z-dn.net/?f=%5Cbegin%7Bgathered%7D%20c%5E2%3D12%5E2%2B9%5E2%20%5C%5C%20c%5E2%3D144%2B81%20%5C%5C%20c%3D%5Csqrt%5B%5Csquare%5D%7B225%7D%20%5C%5C%20c%3D15%5Ctext%7B%20km%7D%20%5Cend%7Bgathered%7D)
The distance between the parents and grandparent house = 15 km
Answer:
I believe the distance is 9
It’s 10.
Good luck my fellow student-
What is the reasonable domain for this function?