MATH QUESTION! for biology.. intense problem..?

In a 3 centimeter leaf, how many guard cells would be on one side of a leaf if there is 5 guard cells shown when the microscope is 43x power? Like when you put the leaf under the microscope, you see 5 cells. If the leaf is 3 centimeters long, using the 5 average of the microscope, how many would be on one whole side of the leaf?