- pointsymmetry
- planesof symmetry
A planeof symmetrymay be a new concept,as it appliesto three-dimensionalobjects.
Line Symmetry
Line symmetryis very familiar. It couldbe called“left-right”symmetry.
A plane(two-dimensional)figurehas aline of symmetryif the figurecan be reflectedover the line and the
imageof everypointof the figureis a pointon the originalfigure.
In effect, this says that the reflectionis the originalfigureitself.
Anotherway to expressthis is to say that:
- the line of symmetrydividesthe figureinto two congruenthalves
- eachhalf can be flipped(reflected)over the line
- and whenit is flippedeachhalf is identicalto the otherhalf
Manyfigureshaveline symmetry, but somedo not haveline symmetry. Somefigureshavemorethan one
line of symmetry.