That depends on the type of cable and which one you bought.
100 feet
Feet
50 feet long
The USB cable is approximately 6 feet long.
A sky cable cord does have a cord that is at least three feet long. In fact the cable cord lengths can very. they can reach up to eight feet long, which is alot in terms of cable cords.
feet or inch
They custom make this cable to any length you need. I believe mine is 15 feet long. Nice cable for the money.
Using Pythagoras' theorem it is 26 feet
5 miles
85 feet
The Monster Networking Dataspeed Network cable is available as short as 7 feet and as long as 100 feet.
You need something called a router. I am not sure if you can just connect the ethernet cable into the computer. If you have a WIRELESS router, you can buy the wireless adaptor for about $100 dollars (new) snd $70 (used). Or you can use the ethernet cable it comes with. The ethernet cable that it comes with is very short (probably 3 1/2 feet long). I got my longer ethernet cable for free, and my free one is about 20 feet long. Wow! All Xbox 360's, besides the Arcade, come with one free month of the Gold Membership. Hope this helped -Joe