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Click on the Y axis to view the ZX plane.
From the Sketching tab, use the Circle tool to draw a circle centered at the origin. Again, Make sure your cursor displays a P near the origin before you begin sketching. Next, use the Line tool to draw two lines along the X and Z axis. We only need to create a quarter of the full sketch to create the 1/8 model. Select the Trim tool and click on any sketch outside the quarter circle enclosed by the lines and the full circle.