1981 AHSME Problems/Problem 20
Problem 20
A ray of light originates from point and travels in a plane, being reflected
times between lines
and
before striking a point
(which may be on
or
) perpendicularly and retracing its path back to
(At each point of reflection the light makes two equal angles as indicated in the adjoining figure. The figure shows the light path for
). If
, what is the largest value
can have?