To measure an angle between points, indicate three points as to form the legs and the apex of the angle.
Click Angle on the Diagnose tab. The cursor changes into a cross hair.
Indicate the first point. A gray sphere appears.
Indicate the second point. A second gray sphere appears and a blue line connects the two spheres.
Indicate the third point. Another gray sphere appears and a blue line connects the spheres.
The angle is measured and visualized by an arch and a value.