# Converting cm to m

• May 31st 2006, 04:53 PM
rob3000
Converting cm to m
Can anyone help me with this.

As part of a physics question a value in centimeters is converted into its metre equivalent but I don't understand how or why.

1358.7 cm^4 = 1358.7 x10^-8 m^4

why is the value in metres x10^-8

Another example of this converts mm to m

eg. 50x150^3 / 12 = 1.406 x10^7 mm^4
= (50x150^3 / 12)x10^-12 m^4
= 1.406 x10^-5 m^4

Again, why to convert from mm to m is x10^-12 used???
• May 31st 2006, 09:33 PM
CaptainBlack
Quote:

Originally Posted by rob3000
Can anyone help me with this.

As part of a physics question a value in centimeters is converted into its metre equivalent but I don't understand how or why.

1358.7 cm^4 = 1358.7 x10^-8 m^4

why is the value in metres x10^-8

Because these are not values in units of centimetres and metres but in units
of centimetres to the power 4, and metres to the power 4. So if there are
100 centimetres in a metre there are (100)^4 centimetres^4 in a metre^4,
and 100^4 is 10^8.

Quote:

Another example of this converts mm to m

eg. 50x150^3 / 12 = 1.406 x10^7 mm^4
= (50x150^3 / 12)x10^-12 m^4
= 1.406 x10^-5 m^4

Again, why to convert from mm to m is x10^-12 used???
Same here, but because there are 1000 millimetres in a metre we have a
scale factor of 1000^4=10^12 between millimetres to the power 4 and
metres to the power 4.

Example consider square centimetres and square metres. There are 10000
square centimetres in a square metre.

RonL