Ubuntu 15.10 VM on windows 7 x64: Need to extend filesystem partition

Hi,
So I've read some posts about this online but I'm not really confident enough in my abilities to pull the trigger on anything I've read.


Heres the problem: I installed ubuntu on virtualbox to a fixed 16gb partition. After dealing with some other issues I had with the installation, I by accident essentially discover that I have, like, 1gb free on the filesystem partition, which for some reason has only decided to use 8gb of the 16 I gave it.


So, first question, why in the world is an essentially brand new Ubuntu installation using of order 8gb?

Second, why is this installation not using the full 16gb allotted it?

Third question, how can I get it to use the full 16gb? Or otherwise extend the filesystem partition?


Looking at the ubuntu disk utility...thing... This is how the partitions are divided up:


- Partition 1: Filesystem, 8.6gb Ext4
- Parition 2: Extended partition, 8.6gb
- Partition 5: Swap, 8.6gb swap


I don't really know how to interpret these partitions and I don't really know how to fix my problem without breaking anything.

Tomorrow I can post pictures from gpart, or anything else you guys need.


Please help, thanks.