The measure angle tool is located on the Tool Bar.
The measure angel tool is used to measure angles between vertices, edges, faces, and volumes. You can also use the measure to drive drive dimensions of geometry.
Select measure tool from the Action Tool Bar or short key M A and and select starting point.
Click and drag handle to the starting vertex.
Use arrows to measure the angle between one point to another.
To change the geometry click on face/edge to change and enter a new angle by clicking on the provided angle.