Step-by-step explanation:
To answer this question, look at the attached vector diagram, where:
d = 1 is the displacement in miles of the bicycle
b = 2 + c = 2 represent the path of the bicycle composed of a displacement of 2.125 miles to the southeast and then a displacement of 1.875 miles to the northwest.
The displacement vector is the distance between the initial point and the end point of the trajectory. Note that the displacement equals the vector d = 1 mile
