SymmetrySymmetry
Two Types:Two Types:
1. Line Symmetry (can1. Line Symmetry (can
be calledbe called reflectionalreflectional
symmetrysymmetry)–)– if youif you
can fold a shape andcan fold a shape and
have the edges meethave the edges meet
 The place where youThe place where you
fold is called thefold is called the lineline
of symmetryof symmetry
More Line SymmetryMore Line Symmetry
reflectional symmetryreflectional symmetry
Line Symmetry in the AlphabetLine Symmetry in the Alphabet
Which letters have got lines of symmetry?Which letters have got lines of symmetry?
A B C D E F G H I
J K L M N O P Q R
S T U V W X Y Z
Click to see the lines of symmetry.Click to see the lines of symmetry.
Lines of Symmetry all around usLines of Symmetry all around us
Which of these road signs have got lines ofWhich of these road signs have got lines of
symmetry?symmetry?Click to see the lines of symmetry.Click to see the lines of symmetry.
CarpetsCarpets
Examples:Examples:
 Do the following shapes have lineDo the following shapes have line
symmetry? If so, how many lines ofsymmetry? If so, how many lines of
symmetry do they have?symmetry do they have?
a. b. c. d. e.a. b. c. d. e.
1 Line1 Line 2 Lines2 Lines 4 Lines4 Lines 2 Lines2 Lines
NoNo
LinesLines
Rotational SymmetryRotational Symmetry
 2. Rotational Symmetry: If you can turn2. Rotational Symmetry: If you can turn
the shape less than 360the shape less than 360oo
and still haveand still have
the same shape.the same shape.
 Order of Rotational Symmetry: Is theOrder of Rotational Symmetry: Is the
number of rotations that must be made tonumber of rotations that must be made to
return to the original orientationreturn to the original orientation
 Minimum Rotational Symmetry: TheMinimum Rotational Symmetry: The
smallest number of degrees a shape cansmallest number of degrees a shape can
be rotated and fit exactly on itselfbe rotated and fit exactly on itself
 Hint: Take 360Hint: Take 360oo
divided by the number ofdivided by the number of
sides/points.sides/points.
Optional – extra information
SymmetrySymmetry
 A figure that hasA figure that has rotational symmetryrotational symmetry is itsis its
own image for some rotation of 180own image for some rotation of 180°° oror
lessless. A figure that has. A figure that has point symmetrypoint symmetry hashas
180180° rotational symmetry.° rotational symmetry.
 A square has 90° and 180° rotationalA square has 90° and 180° rotational
symmetry with the center of rotation at thesymmetry with the center of rotation at the
center of the square. A square also hascenter of the square. A square also has
point symmetry.point symmetry.
Identifying Rotational SymmetryIdentifying Rotational Symmetry
 Identify any rotational symmetry in theIdentify any rotational symmetry in the
figure.figure.
Identifying Rotational SymmetryIdentifying Rotational Symmetry
 This figure has rotational symmetry, It willThis figure has rotational symmetry, It will
coincide with itself after being rotated 90coincide with itself after being rotated 90°°
or 180° in either direction.or 180° in either direction.
Identifying Rotational SymmetryIdentifying Rotational Symmetry
 This figure has rotational symmetry. It willThis figure has rotational symmetry. It will
coincide with itself after being rotated 60coincide with itself after being rotated 60°°,,
120120°°, or 180, or 180°° in either direction.in either direction.
Identifying Rotational SymmetryIdentifying Rotational Symmetry
 This figure has no rotational symmetry. ItThis figure has no rotational symmetry. It
does have horizontal line of symmetry.does have horizontal line of symmetry.
Examples:Examples:
Rotational Symmetry all aroundRotational Symmetry all around
usus
Which road signs have got rotational symmetry?Which road signs have got rotational symmetry?
Click to see the answers.Click to see the answers.
Rotational Symmetry all aroundRotational Symmetry all around
usus
Which road signs have got rotational symmetry?Which road signs have got rotational symmetry?
Rotational Symmetry all aroundRotational Symmetry all around
usus
Order 3 Order 2 Order 2
Rotational Symmetry all aroundRotational Symmetry all around
usus
Order 4 Order 3 Order 2
Rotational Symmetry all aroundRotational Symmetry all around
usus
Order 3 Order 2

10 6 symmetry lesson

  • 1.
    SymmetrySymmetry Two Types:Two Types: 1.Line Symmetry (can1. Line Symmetry (can be calledbe called reflectionalreflectional symmetrysymmetry)–)– if youif you can fold a shape andcan fold a shape and have the edges meethave the edges meet  The place where youThe place where you fold is called thefold is called the lineline of symmetryof symmetry
  • 2.
    More Line SymmetryMoreLine Symmetry reflectional symmetryreflectional symmetry
  • 3.
    Line Symmetry inthe AlphabetLine Symmetry in the Alphabet Which letters have got lines of symmetry?Which letters have got lines of symmetry? A B C D E F G H I J K L M N O P Q R S T U V W X Y Z Click to see the lines of symmetry.Click to see the lines of symmetry.
  • 4.
    Lines of Symmetryall around usLines of Symmetry all around us Which of these road signs have got lines ofWhich of these road signs have got lines of symmetry?symmetry?Click to see the lines of symmetry.Click to see the lines of symmetry.
  • 5.
  • 6.
    Examples:Examples:  Do thefollowing shapes have lineDo the following shapes have line symmetry? If so, how many lines ofsymmetry? If so, how many lines of symmetry do they have?symmetry do they have? a. b. c. d. e.a. b. c. d. e. 1 Line1 Line 2 Lines2 Lines 4 Lines4 Lines 2 Lines2 Lines NoNo LinesLines
  • 7.
    Rotational SymmetryRotational Symmetry 2. Rotational Symmetry: If you can turn2. Rotational Symmetry: If you can turn the shape less than 360the shape less than 360oo and still haveand still have the same shape.the same shape.  Order of Rotational Symmetry: Is theOrder of Rotational Symmetry: Is the number of rotations that must be made tonumber of rotations that must be made to return to the original orientationreturn to the original orientation  Minimum Rotational Symmetry: TheMinimum Rotational Symmetry: The smallest number of degrees a shape cansmallest number of degrees a shape can be rotated and fit exactly on itselfbe rotated and fit exactly on itself  Hint: Take 360Hint: Take 360oo divided by the number ofdivided by the number of sides/points.sides/points. Optional – extra information
  • 8.
    SymmetrySymmetry  A figurethat hasA figure that has rotational symmetryrotational symmetry is itsis its own image for some rotation of 180own image for some rotation of 180°° oror lessless. A figure that has. A figure that has point symmetrypoint symmetry hashas 180180° rotational symmetry.° rotational symmetry.  A square has 90° and 180° rotationalA square has 90° and 180° rotational symmetry with the center of rotation at thesymmetry with the center of rotation at the center of the square. A square also hascenter of the square. A square also has point symmetry.point symmetry.
  • 9.
    Identifying Rotational SymmetryIdentifyingRotational Symmetry  Identify any rotational symmetry in theIdentify any rotational symmetry in the figure.figure.
  • 10.
    Identifying Rotational SymmetryIdentifyingRotational Symmetry  This figure has rotational symmetry, It willThis figure has rotational symmetry, It will coincide with itself after being rotated 90coincide with itself after being rotated 90°° or 180° in either direction.or 180° in either direction.
  • 11.
    Identifying Rotational SymmetryIdentifyingRotational Symmetry  This figure has rotational symmetry. It willThis figure has rotational symmetry. It will coincide with itself after being rotated 60coincide with itself after being rotated 60°°,, 120120°°, or 180, or 180°° in either direction.in either direction.
  • 12.
    Identifying Rotational SymmetryIdentifyingRotational Symmetry  This figure has no rotational symmetry. ItThis figure has no rotational symmetry. It does have horizontal line of symmetry.does have horizontal line of symmetry.
  • 13.
  • 14.
    Rotational Symmetry allaroundRotational Symmetry all around usus Which road signs have got rotational symmetry?Which road signs have got rotational symmetry? Click to see the answers.Click to see the answers.
  • 15.
    Rotational Symmetry allaroundRotational Symmetry all around usus Which road signs have got rotational symmetry?Which road signs have got rotational symmetry?
  • 16.
    Rotational Symmetry allaroundRotational Symmetry all around usus Order 3 Order 2 Order 2
  • 17.
    Rotational Symmetry allaroundRotational Symmetry all around usus Order 4 Order 3 Order 2
  • 18.
    Rotational Symmetry allaroundRotational Symmetry all around usus Order 3 Order 2