Lesson on Rotation Symmetry

Introduction

What do you say when the hands of a clock go round?

You say that they rotate. The hands of a clock rotate in only

one direction, about a fixed point, the center of the clock-face.

Rotation, like movement of the hands of a clock, is called

a clockwise rotation; otherwise it is said to be anticlockwise.​

Rotational Symmetry

By Deshna, Ishika, Jiyareet, Janisha, Gaurika

What Is Rotational Symmetry?

​Rotational symmetry is a shape when it looks the same even after rotation as it has started from its starting point example clock, wheels, fan 

The center of rotation is a point that is the same distance from any pair of corresponding points. 

What is Centre Of Rotation ?

The angle by which the object rotates is called the angle of rotation. A half-turn means rotation by 180. Example: A regular hexagon has rotational symmetry. 

 

Angle of Rotation 

Multiple Choice

A figure has __________ of symmetry if there is a line about which the figure may be folded so that the two parts of the figure coincide.

• None

• Line

• Symmetry

• All

Multiple Choice

A regular pentagon has ____________ line (s) of symmetry.

• 10

• 2

• 5

• 1

Multiple Choice

A figure has ____________ symmetry if after a rotation through a certain angle. The figure looks exactly the same.

• All

• Rotational

• 5

• None

Draw

Show rotational Symmetry

Multiple Choice

Each of the letters H, N, S and Z has a rotational symmetry of order __________.

• 1

• 2

• 5

• 6

Multiple Choice

The line of symmetry of an isosceles triangle is its ______________________ from the vertex having the equal sides.

• None Of the Above

• Rotational and Altitude

• Altitude and angles

• Median and Altitude

Multiple Choice

A __________ triangle has no lines of symmetry

• Sclene

• Scalne

• Scalene

• Scelene

Multiple Choice

Each regular polygon has as many lines of symmetry as it has _____________.

• number of sides

• number of angles

• number of corner

• I don't Know

Open Ended

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