In her job as a dental hygienist, Kathryn uses a concave mirror to see the back of her patient's teeth. When the mirror is 1 . 4 0 c m from a tooth, the image is upright and 3 . 6 0 times as large as the tooth. Problem 2 3 . 0 5 0 - 1 - Focal length of the mirror What is the focal length of the mirror?