Rhombus CDEF is shown below. If the slope of FC is 25, what must be the slope of CD in order for CDEF to be a square?

Can someone show me the steps to solve the problem?

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

Simplify the following expression 48^1/2