You can use Google Maps to find out which direction north is.
Steps

Step 1. Open Google Maps
Look for the icon called Maps on your Android phone. It represents a map and is usually located on the home screen.

Step 2. Press the Locate button
It can be found in the lower right corner of the map. It is a black dot inside a sighting reticle in a white circle.

Step 3. Press the Compass
It is the icon representing a white and red arrow at the top right of the screen.

Step 4. Find north
The map will rotate and when the letter "N" appears, the red tip of the needle will point north.