Please help me. I really need it.

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

What is the approximate value of the correlation coefficient for the given graph? a. 1 b. 5 c. 3 d. -1

Fifty students are trying to raise at least 12,500 for a class trip. they have already raised 1,250. how much should each student raise on average in order to meet the goal? write and solve the two step inequality for this problem