What are the angles of rotation for a 20-gon how many lines of symmetry lines of reflection will it have?

Here my dog "Flame" has her face made perfectly symmetrical with a bit

Inhaltsverzeichnis Show

of photo magic.

The white line down the center is the
Line of Symmetry

Read more at Reflection Symmetry.

You can find if a shape has a Line of Symmetry by folding it.

When the folded part sits perfectly on top (all edges matching), then the fold line is a Line of Symmetry.

Here I have folded a rectangle one way, and it didn't work.

So this is not a Line of Symmetry

But when I try it this way, it does work (the folded part sits perfectly on top, all edges matching):

So this is a Line of Symmetry

Triangles

A Triangle can have 3, or 1 or no lines of symmetry:

Equilateral Triangle (all sides equal,

all angles equal)

Isosceles Triangle (two sides equal,

two angles equal)

Scalene Triangle (no sides equal,

no angles equal)

3 Lines of Symmetry

1 Line of Symmetry

No Lines of Symmetry

Different types of Quadrilaterals (a 4-sided plane shape):


Square (all sides equal, all angles 90°)	Rectangle (opposite sides equal, all angles 90°)	Irregular Quadrilateral
4 Lines of Symmetry	2 Lines of Symmetry	No Lines of Symmetry


Kite		Rhombus (all sides equal length)
1 Line of Symmetry		2 Lines of Symmetry

A regular polygon has all sides equal, and all angles equal:

	An Equilateral Triangle (3 sides) has 3 Lines of Symmetry
		A Square (4 sides) has 4 Lines of Symmetry
	A Regular Pentagon (5 sides) has 5 Lines of Symmetry
		A Regular Hexagon (6 sides) has 6 Lines of Symmetry
	A Regular Heptagon (7 sides) has 7 Lines of Symmetry
		A Regular Octagon (8 sides) has 8 Lines of Symmetry