To add the apps mentioned below to your Google Hangout, follow these steps : Head over to your Google Hangout, hover your mouse over the dots as is shown in the screenshot below and then click on " add apps". A new window will pop up featuring a variety of apps. Look for the ones mentioned in the list then add them.
Now here is a set of our favorite apps to use with your hangouts:
1- Remote Desktop
A Hangouts app for people to help other people with their computers, by controlling them remotely (with their permission, of course).
2- Google Drive
This app allows you to access and edit your Google Drive files together
A digital whiteboard with sticky notes. You can use it for to-do's, brainstorming, meetings, planning and much more.
This one lets you discuss presentations with your friends.
5- Cacoo for Hangouts
Cacoo is user friendly online drawing tool. It supports real time collaboration meaning muliple users can edit and work on the same diagram synchronously.