# Homework Help: How many square centimeters is a square meter?

1. Dec 10, 2008

### Haibara Ai

How many square centimeters is a square meter, and how many square meters a square kilometer? thanks

2. Dec 10, 2008

### Mentallic

Re: Areas

There is an easy way to figure out these problems, but its pointless if you don't understand the reasoning behind it.

Take a metre, and square it to have a metre squared. Now realize that 1 metre = 100 centimetres by definition. This means you can fit 100 centimetres along the metre-squared's length, and 100 centimetres along the metre-squared's width. Now, you should know that the area = length * breadth. So area = 100cm * 100cm = 10,000cm2

Thus, 1m2=10,000cm2=1002cm2

As for the square kilometre. There are 1000 metres in 1km. So if we take 1km2, we can fit 1000m along the length, and 1000m along the width. Area=1000m*1000m=1,000,000m2

Thus, 1km2=10002m2=1010cm2

Similarly, you can do this for volumes.

e.g. 1m3 is how many cm3? Well, 100cm=1m, and volume = length * breadth * height = 100cm*100cm*100cm = 1,000,000cm3=106cm3

In summary ~ For area, to find the amount of m2 to km2 or cm2 to mm2 etc. Just realize how many of those units are equal to the other larger/smaller metric unit, and square it. For volumes, cube it.

3. Dec 11, 2008

### Haibara Ai

Re: Areas

Ok, thanks a lot

4. Dec 11, 2008

### bobmerhebi

Re: Areas

Hello, can any one tell me why is the area of a wire pi (r/2)^2 & not that of a cylinder 2pi.rl ? thx

5. Dec 11, 2008

### HallsofIvy

Re: Areas

$2\pi r l$ is the area of the curved surface of a cylinder of radius r and length l. It does not include the area of the two circular bases.

And in the future, remember that it is better to start your own thread than add a new question onto another person's.

6. Dec 11, 2008

### LowlyPion

Re: Areas

Are you asking about the cross sectional area of the wire which is π(d/2)² since wire gauges are usually given as diameters?

Or as Halls of Ivy has asked if you wanted the area of the entire radial surface of the wire without the cross sections?