The area for any square is given by the function y=x squared where is the length of a side of the area square and y is the area of the square write the equation i'm function notation and find the area of a square with a side length of 3.5 inches

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