Can someone help me simplify radical numbers in geometry?

[Lou1024]

Hey everyone,
My class recently started radical numbers, and I haven't a clue on how you simplify them!
Heres a few of my homework problems. if someone could possibly walk me through how you do them It would be greatly appreciated.

http://img495.imageshack.us/img495/6903/math0oj.png

Sorry for the bad paint job :)
Thanks,

Lou

 

[JasonRox]

I'll write you one.

sqrt(20) = sqrt(4*5) = 2*sqrt(5)

See what I did? I found perfect scares and are part of the product of the number 20.

I believe that's what you're doing.

 

[JasonRox]

http://www.purplemath.com/modules/radicals.htm

Here is a good link too.

 

[Lou1024]

ah ok thanks, I understand that part. But what do you do for division, or when you have a number before the square root?

 

[Lou1024]

Thanks for the link.