Question: 1 cm of rain equals how much water?
Answer: 10 millimetres is a centimetre and there are 100 centimetres in a metre so you have 1 cm of rain over 100 × 100 = 10000 square cms. That is a volume of 1 × 10000 = 10000 cubic centimetres. One cubic centimetre is a millilitre and hence the volume of water is 10000 milliletres.