This tutorial explains how to share your location with other users with the Google Hangouts app on an Android smartphone. You can share your location through a classic Hangout message or SMS message, but first you should make sure that Location Sharing is enabled (Settings > Location) on your smartphone and that Google Hangouts has access to GPS, Wi-Fi and cellular network.
Google Hangouts has the ability to detect phrases such as "Where are you?" in your conversations and will automatically display the (1) Share your location prompt. But you can also tap on the (2) Share Location button located below the message field to achieve the same result:
Google Hangouts displays your current location on a map, as well as a list of Nearby Places (restaurants, hotels, station...).