There are 10000 micrometres in one centimetre. Therefore, 3 centimetres is equal to 3 x 10000 = 30000 micrometres.
There are 0.001 millimetres in one micrometre.
There are one million micrometres in one metre. Therefore, 2.6 metres is equal to 2.6 x 1000000 = 2600000 micrometres.
There are 1000 micrometres in one millimetre. Therefore, 100 micrometres is equal to 100/1000 = 0.1 millimetres.
7.5 micrometres is equal to 0.00075 centimetres.