Question on resolution with Virtual Box

[AVIorDIE]

Hello everyone,
I just downloaded and installed Backtrack 5r3 with KDE and I installed it on Virtual Box, I ran into an issue. I have a 1600x900 resolution monitor but my Virtual Box will on go up to what you see in the picture below. Is there a way to increase the resolution? If so, please let me know! Sorry for the size of the photo.
Why.jpg

[fuzamaru]

control(right) + f

[Jimmy87]

Is there some guest additions you need to install for VirtualBox?

I run it in VMWare and if I resize the VM window, BT5 automatically resizes to fit the window.

[AVIorDIE]

I think I still do need the guest additions thanks for reminding me that is probably it.