Please help-- Area of triangle PQR = 10.2 square units

Area of triangle PRS = 11.5 square units

Area of triangle PST = 16.3 square units

The area of Figure PQRST is

square units. (Input whole number only.)

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