You should wrap your code in <pre> </pre> tags, so that we can see the indenting. Alternatively, it would be nice to see a syntax highlighter. Such code exists in PHP.
A several things now...
It would be nice to see some more meaningful variables names.
Comments are always good. I still haven't found a single comment in any of your programs.
Check your input for validity. How do you know the user isn't inputting any trash? How can you be sure he/she selected one of the options provided?
Likewise, make sure you aren't dividing by zero. What if the user enters in 0 for #2 in Chapter 1?
Furthermore, make sure you aren't square rooting a negative number. The user could easily enter a negative number for #1 in Chapter 2.
As Hurkyl suggested, you need to specify the environment. People don't like finding code that won't work on their compiler. Better yet, write the code so its portability is not restrticed in the first place.
Don't use labels and/or the goto statement. This is generally horrible coding practice. Although the script kiddies will understand your code, Bjarne Stroustrup would come straight to your doorstep and set you straight, if it weren't for so many others making the same mistake. The only time a goto is ever tolerated, is whilst exiting an extremely deeply nested loop. And even then, the question how you got there in the first place is brought to attention. I'd suggest that you return, instead of using a goto.
You are placing things that suggest a subroutine, by nature, into main. Although this is tolerable, a better programming habit would lead you to fold your routines into separate functions, pass in the appropriate values from main, and output the corresponding message afterwards. The advantage to this, is people would actually find it beneficial to make use of your code, in light of it being extendable to something useful.
My mouse wheel is getting worn down, so I'll stop here at Chapter 2. I don't mean to discourage you. I'd just like to see some of this shaped up a little. You have something to offer, it would be nice to see it offered to the extent of your abilities. It's not kind to misguide others into poor programming habits.
If you require any clarification of any ideas I have suggested, please ask. I'd like to help you strengthen your website.