How if a cell being observed has been magnified 200x under the HPO what is the magnifying power of the eyepiece used?

To determine the magnifying power of the eyepiece used, you can divide the total magnification by the objective lens magnification. If the cell is observed at a total magnification of 200x under the High Power Objective (HPO), which typically has a magnification of 40x, the eyepiece magnification can be calculated as follows: 200x (total magnification) ÷ 40x (HPO) = 5x. Therefore, the eyepiece used has a magnifying power of 5x.