Right-click Sketch1 and select Edit Sketch.
Click Add
Relation 
(Dimensions/Relations
toolbar).
In the graphics area, select the bottom left point.
Right-click Sketch1 and select Edit Sketch.
Click Add
Relation (Dimensions/Relations
toolbar).
In the graphics area, select the bottom left point.
In the PropertyManager,
under Add Relations,
click Fix 
.
In the graphics area, select the horizontal line.
In the PropertyManager,
under Add Relations,
click Horizontal 
, then click 
.
