21 cm equals 0.00021 km. To convert cm to km, divide the number of cm by 100000.
cm to km conversion can be done using multiplication or division.
First, let’s convert 21 cm to km using multiplication method:
We know that there are 0.00001 kilometers in a cm.
km = number of cm × 0.00001
thus, 21 cm = (21 × 0.00001) km
∴ 21 cm = 0.00021 km
Next, let’s convert 21 cm to km by using the division method:
There are 100000 cm in a km. To use division method of conversion, we will use following formula:
km = number of cm ÷ 100000
thus, 21 cm = (21 ÷ 100000) km
∴ 21 cm = 0.00021 km
How many km are there in 21 cm?
There are 0.00021 km in 21 cm.