Google announced a new Google Hangouts with Extras feature that lets you make phone calls from inside Hangouts.
In the announcement on Google+, Google’s Jarkko Oikarinen said, “We are constantly listening to feedback so that we can make Hangouts even better for Google+ users, and we're excited by the really cool ways people are using the product. Today we’re making it possible to make phone calls from inside a hangout, so you can dial people into the room from wherever they’re at. (Helpful for party lines and conference calls alike.)”
For now, the feature only supports calls in the U.S. and Canada, and they’re free. The feature can be found in Google+ Hangouts with Extras.
Google announced Hangouts with Extras back in September as part of a handful of Google+ feature announcements, which also included search. Other extras include: SketchPad and Google Docs support and Hangout naming.
To add a phone participant to a hangout, click “invite” at the top of the Hangouts with Extras window, click the “phone” tab on the left of the window, and enter the phone number of the person you want to call. Then click “call now”.