The figure for this problem shows a light ray entering a region between two parallel flat mirrors at point A.

Theray travelsbetween thetwo mirrors from pointA to pointG to point C to point I, and it leaves the region between these two mirrors at point I so that the lines AG and CI are parallel. If the distance between the two parallel mirrors is y =20 cm and if the distance x marked in the figure is x =40 cm,

a.) (10 points) determine the value of the angle θ,and

b.) (10 points) determine the distance between the points E and C in the figure.