**Definitions:**

**Kilometer** (abbreviation: **km**): is a unit of length in the SI metric system, equal to one thousand metres (kilo- being the prefix for 1000). It is now the measurement unit used officially for expressing distances between geographical places on land in most of the world countries.

**Millimeter** (abbreviation: **mm**): is a unit of length in the SI metric system, equal to one thousandth of a metre. Therefore, there are thousand millimetres in a metre and ten millimetres in a centimetre.

## How to Convert Kilometers to Millimeters

*Example: How many millimeters are equivalent to 51.43 kilometers?*

As;

1 kilometers = 1000000 millimeters

51.43 kilometers = Y millimeters

Assuming Y is the answer, and by criss-cross principle;

Y equals 51.43 times 1000000 over 1

(i.e.) Y = 51.43 * 1000000 / 1 = 51430000 millimeters

Answer is: 51430000 millimeters are equivalent to 51.43 kilometers.

*Practice Question: Convert the following units into mm:*

N.B.: After working out the answer to each of the next questions, click adjacent button to see the correct answer.

( i ) 35.12 km

( ii ) 19.6 km

( iii ) 50.78 km