In some circumstances the sketch grid does not align with the vertices and lines of the sketch or the underlying reference geometry. You may find it easier to create the desired sketch if you use Sketcher customization options to realign the sketch grid. The customization options allow you to do the following:
Shift the grid relative to the sketch by selecting a vertex representing the origin of the grid. To help you locate the origin of the sketch, the X- and Y-axes of the sketch are indicated by dashed lines that intersect at the origin.
Rotate the grid relative to the sketch by selecting a line from the sketch that will be parallel to the X-axis of the grid.
To realign the sketch grid:
From the bottom of the Sketcher toolbox, select the customization tool 
.
The Sketcher Options dialog box appears.
From the buttons across the center of the dialog box, do the following:
Click Origin to move the origin of the sketch grid relative to the part. Select the new origin from the sketch or type the coordinates of the origin in the prompt area.
Click Angle to rotate the sketch grid relative to the part. Select a line that will be parallel to the X-axis of the sketch.
Click Reset to restore the original sketch origin and to restore the original alignment of the X-axis.
After you have chosen the desired customization options, click OK to apply your changes and to close the Sketcher Options dialog box.
