More Lessons for Grade 9 Math
Examples, solutions, videos, worksheets, games and activities to help Geometry students learn about line symmetry and plane symmetry.
The following diagram shows the line of symmetry for quadrilaterals and triangles. Scroll down the page for more examples and solutions on lines of symmetry.
Reflection Symmetry (or Line Symmetry) and Rotational Symmetry
Symmetry in a figure exists if there is a reflection, rotation, or translation that can be performed and the image is identical. Reflectional symmetry exists when the figure can be folded over onto itself along a line. This line is called the "line of symmetry". In regular polygons, the number of lines of symmetry equals the number of sides in the polygon.
Line Symmetry and Rotational Symmetry
Learn to identify lines of symmetry and rotational symmetry
Plane symmetry is analogous to line symmetry, except that it is in three dimensions. The three dimensional figure is divided into two halves by a plane.
The following diagram shows the planes of symmetry of a cuboid or rectangular solid.
Plane symmetry and axis symmetry
Examples of plane symmetry and axis symmetry
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