Answer:
20.6 miles to the nearest tenth.
Explanation:
The 3 journeys form a right triangle with the hypotenuse equal to the length of the path from Quinn's house to Gabrielle's home.
By Pythagoras:
8.9^2 = 3.6^2 + x^2 where x is the distance from the school to Quinn's house.
x^2 = 8.9^2 - 3.6^2 = 66.25
x = √66.25
x = 8.14 miles
So the distance Gabrielle bikes each day
= 3.6 + 8.9 + 8.14
= 20.64 miles