Sketcher > Dimensioning Sketcher Geometry > Working with Dimension Tools > Normal Dimensions > To Create an Angle Dimension Defined by Three Points
  
To Create an Angle Dimension Defined by Three Points
1. Right-click in the Sketcher window and choose Dimension from the shortcut menu or click Sketch > Normal.
2. Select the first point.
3. Select a point for the angle vertex.
4. Select the second point.
5. Middle-click to place the dimension. The dimension is placed.