Answer:
13.7
Step-by-step explanation:
It forms a triangle.
They are trying to find the height, cause they say the east-bound car went east so that makes the bottom of the triangle, the width. They also give is the distance in between both cars so that's the hypotenuse so let's set up the equation...
15² - 6² = 189
now we square root it
√189 = 13.7