Final answer:
Priya likely measured the circumference of the bike wheel, which is the distance around the edge of the circle, relevant to calculating the distance traveled per rotation.
Step-by-step explanation:
The part of the circle Priya measured on the bike wheel is most likely the Circumference. The circumference is the distance around the edge of the circle and is calculated using the formula 2πr, where r represents the radius of the circle. Since the task of measuring a bike wheel typically involves getting the length around it, which is important for things like determining the distance traveled per rotation, the circumference is the logical part to measure.