A microscope has an objective lens with a focal length of 16.22 mmand an eyepiece with a focal length of 9.20 mm. With the length of the barrel set at31.0 cm, the diameter of a red bloodcell's image subtends an angle of 1.43 mrad with the eye. If thefinal image distance is 31.0 cm from theeyepiece, what is the actual diameter of the red blood cell?