Answer:
200 feet
Explanation:
According to my research on the studies conducted by motor vehicles safety professionals, It is said that based on the information provided within the question the driver needs a mirror in which he/she is able to view the roadway 200 feet to the rear of the vehicle. This is a safety precaution which allows the driver a broader environmental awareness leading to less accidents.
I hope this answered your question. If you have any more questions feel free to ask away at Brainly.