What is the name of the line of reflection for the pair of figures?

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters

Given sin28.4=.4756, cos28.4=.8796, and tan28.4=.5407 find the cot of 61.6

What are the greatest common factor of 75 and 30