The cell’s actual size is 0.10.10.1 mm (which is the same as 100100100 µm).

Quick Scoop

To get the real (actual) size of a cell from a magnified image, use the standard magnification formula:
magnification = image size ÷ actual size. Rearranging, actual size = image size ÷ magnification.

Here:

  • Image size = 10 mm.
  • Magnification = 100×.

So:

  • Actual size = 10 mm÷100=0.1 mm10\text{ mm}÷100=0.1\text{ mm}10 mm÷100=0.1 mm.
  • In micrometres, 0.1 mm=100 µm0.1\text{ mm}=100\text{ µm}0.1 mm=100 µm.

So if a cell measures 10 mm at ×100 magnification, its real size is 0.1 mm (100 µm).

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