Answer:
d = 15 miles
Explanation:
To get to his parents’ house, Ruben would have to drive due north 12 miles.
To get to his grandparents’ house, he would have to drive due east 9 miles.
It is required to find the distance between the parents’ and grandparents’ houses.
First distance is 12 miles and second distance is 9 miles.
So,

So, the distance between the parents’ and grandparents’ houses is 15 miles.