Symmetrical elements lie on opposite sides of an axis of symmetry and behave as mirror images of each other. You can use the Symmetry constraint to create a symmetrical relationship between sketch elements.
To create a Symmetry constraint:
- Select two similar elements, such as two arcs or two lines.
- Select Symmetry from the constraints menu.
- Select a line or an edge for the axis of symmetry.
Learn more by watching the video below: