If there are 669 cells in 11 out of 15 views on the microscope, then how many cells would be in a transect of 40 views?

I used to count Asbestos particles in cells. We would take a fiber average in all the cells , 10X10, some had none, some had 4 and then extrapolate for the full screen, many thousand cells. Look at your proportions, how many cells had nothing? What is 669/11-that is an average cells per view. You have to assume the same ratio for 40 cells 11/15=X/40