Sketcher > Dimensioning Sketcher Geometry > Working with Dimension Tools > Normal Dimensions > To Create an Angle Dimension between Lines
  
To Create an Angle Dimension between Lines
1. Right-click in the Sketcher window and choose Dimension from the shortcut menu or click Sketch > Normal.
2. Select the first line.
3. Select the second line.
4. Middle-click to place the dimension. The dimension is placed.
 
* Dimension placement determines whether the acute or obtuse angle is measured.