Answer:
Diameter of the cell will be 0.012 mm.
Explanation:
The diameter of a white blood cell under magnification was 0.3 centimeters.
Since 1 centimeter = 10 mm
Therefore, 0.3 cm = 0.3×10
= 3 mm
If a microscope has a scale of 250 : 1
Then diameter will be in the same ratio.
=

=

Original diameter of the cell =

= 0.012 mm