To find the focal length of a convex mirror , a student records the following data:
`{:("Object Pin","Convex Lens","Convex mirror","Image Pin"),(22.2 cm,32.2 cm,45.8 cm,71.2 cm):}`
The focal length of the convex lens is `f_(1)` and that of mirror is `f_(2)` . Then taking index correction to be negligibly small , `f_(1)` and `f_(2)` are close to :