How to Install KDE SC 4.9 on Ubuntu 12.04 LTS

The following tutorial was created especially for those of you who want to install KDE SC 4.9 on their Ubuntu 12.04 LTS (Precise Pangolin) machines. In other words, with this guide, we will teach you, step by step, how to install KDE SC 4.9 on top of your existing Ubuntu 12.04 LTS (Precise Pangolin) installation.