Symmetry in Polygons

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Concept of Symmetry

Symmetry: When one Shape become exactly like other after turning, sliding and flipping it.
Symmetry is of three types: Linear Symmetry, Point Symmetry and Rotational Symmetry.

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Line of Symmetry

Line which divides a figure into two symmetrical figures, then that line is known as Line of Symmetry.

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Line of Symmetry in an Isosceles Triangle

In an Isosceles Triangle, Line of Symmetry bisects the angle  enclosed by two equal sides and divides side opposite to that angle into equal parts.

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Lines of Symmetry in an Equilateral Triangles

In an Equilateral Triangle, there are Lines of Symmetry along the Medians.

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Lines of Symmetry in a Rectangle and a Rhombus

In Rectangle, there are Two Lines of Symmetry.
In Rhombus, there are Two Lines of Symmetry

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Lines of Symmetry in a Regular Polygon

Lines of Symmetry in a Regular Polygon is equal to number of sides of Polygon, since in Regular Polygon all sides are Equal.

result

Anticlockwise rotation

Rotation of point through 90 about the origin in anticlockwise direction when point M (h, k) is rotated about the origin O
through 90 in anticlockwise direction. The new position of point M (h, k) will become M' (-k, h).

Find the new position of the A (2, 3)  point when

rotated through 90 anticlockwise about the origin.
solution:

When rotated through 90 about the origin in anticlockwise

direction. The new position of the above point is:The new position of point A (2, 3) will become A' (-3,2)