Line Symmetry

The concept of line symmetry or reflectional symmetry is closely related to mirror reflection.

A shape has line symmetry when one half of it is the mirror image of the other half.

A mirror line, thus, helps to visualise a line of symmetry.

Draw all axes of symmetry in these six images and shapes:

Lines of Symmetry for Regular Polygons

You know that a polygon is a closed figure made of several line segments.

The polygon made up of the least number of line segments is the triangle. (Can there be a polygon that you can draw with still fewer line segments? Think about it).

A polygon is said to be regular if all its sides are of length and all its angles are of measure.

Thus, an equilateral triangle is a regular polygon of three sides.

Can you name the regular polygon of four sides?

An equilateral triangle is regular because each of its sides has same length and each of its angles measures ° .

A square is also regular because all its sides are of length and each of its angles is a right angle (i.e., °). Its diagonals are seen to be perpendicular bisectors of one another.

If a pentagon is regular, naturally, its sides should have equal length. You will, later on, learn that the measure of each of its angles is 108°.

A regular hexagon has all its sides equal and each of its angles measures °. You will learn more of these figures later.

The regular polygons are symmetrical figures and hence their lines of symmetry are quite interesting,

Each regular polygon has as many lines of symmetry as it has sides. We say, they have multiplesingle lines of symmetry.

In the below given regular polygons, draw their respective axes of symmetry and add in the number of axes possible in the provided blanks

Perhaps, you might like to investigate this by paper folding. Go ahead!