Perpendicular Snap tool

Use the Perpendicular Snap tool to snap to the perpendicular point of another entity. You can snap to an arc, circle, ellipse, line, polyline, infinite line, ray, spline, hatch pattern, or edge of a plane to form a perpendicular alignment with that entity or with an imaginary extension of that entity.    

To set the Perpendicular Snap    

Do one of the following to choose Perpendicular Snap ():

    On the ribbon, choose Draw > Perpendicular Snap (in Entity Snaps).

    On the menu, choose Tools > Entity Snap > Perpendicular Snap.

    On the Entity Snaps toolbar, click the Set Perpendicular Snap tool.

    Type perpendicular and then press Enter.