3 cm = 30000 µm is your answer.

I believe a micrometer is a millionth of a meter. A centimeter is a hundredth of a meter. Soooo

1,00,000 / 100 = 10,000 centimeters in a micrometer, x 3 cm. = 30,000

So there are 30,000 micrometers in 3 centimeters.

1,00,000 / 100 = 10,000 centimeters in a micrometer, x 3 cm. = 30,000

So there are 30,000 micrometers in 3 centimeters.