Angle Measurement
Function Description: The angle measurement tool allows you to interactively select measurement points using a mouse click and query the pitch angle between three points in a 3D view.
Steps
1.Click the "Angle" 
button in the "Measure" menu.
2.In the 3D view window, left-click the data points one by one with your mouse to select three points. The angle formed by these points is the measured angle (as shown in the figure).
3.You can right-click the mouse before completing the measurement to go back and deselect one point.
Note: This feature is only available in the 3D view window.