How to resize the root partition using GParted

I'm new to GParted. I have to resize a partition that contains root file system which is full. Previously I had Windows installed in my system. I use a 250GB hard drive and was divided into 3 drives namely C, D and E drive. After this I installed Ubuntu and used the existing NTFS file system, to install Ubuntu. Now, I need to resize the partition mounted on root file system as it is full.
Below is the link to screenshot of GParted -

What should I do to increase the size the /dev/sda6 without any data loss in GParted

Solution 1:

1. Download Gparted Live CD .iso from here and burn it using Brasero
2. Boot from it
3. skip language
4. To start up the default graphical environment Press Enter
5. That's is Now start Gparted