Select Sketch | Lines | Two Point Line. More options...Less options...
(OR) Select the context-sensitive function Line > Two point rectangle.
You can add automatic guide curves from corner to corner or from middle to middle. Select No helplines, Helplines from corner to corner or Helplines from side to side.
Select the center point of the rectangle.
Finish the rectangle by selecting its corner point. Perpendicular constraints are added to the sides of the rectangle.
Draw more two point rectangles by repeating steps 2 and 3 or finish drawing two point rectangles by pressing the ESC key or the middle mouse button.
Two Point Line. 
Line > 
Two point rectangle.
No helplines, 
Helplines from corner to corner or 
Helplines from side to side.