Symmetry Objective Today we will identify types of
Symmetry Objective: Today, we will identify types of symmetry in figures.
Reflectional Symmetry/Line Symmetry • A figure has reflectional symmetry if and only if a line coincides with the original figure. • The line is called the axis of symmetry.
Reflectional Line of Symmetry • A figure has reflectional symmetry if and only if there exists a line that “cuts” the figure into two congruent parts, that fall on top of each other when folded over the line of symmetry.
Rotational Symmetry • A figure has rotational symmetry of “n” degrees if you can rotate the figure “n” degrees and get the exact same image. • N must be between 0 and 360.
Rotational Symmetry • Wind Mill • How many degrees can each rotate?
Point Symmetry • A figure has point symmetry when a rotation of 180 degrees maps the figure onto itself. • (It looks exactly the same upside down)
Examples Name all the types of symmetry each figure has: (if rotational state how many degrees) Rotational Symmetry (180) Reflectional Or Point Symmetry (1) Reflectional Symmetry (8) Rotational Symmetry (45)
Alphabet Language Horizontal Vertical Line ENGLISH (Uppercase) GREEK Line Rotational Symmetry
Greek Alphabet
Language ENGLISH GREEK Horizontal Line Vertical Line Rotational Symmetry
IS IT SYMMETRICAL? Directions • Take your paper, fold it so there are 4 sections. • Label each with Horizontal ONLY, Vertical ONLY, Both H &V, and/or Rotational
Which category does it fit? • Directions: Draw each picture under the correct type of symmetry.
Which category does it fit?
Which category does it fit?
Which category does it fit?
- Slides: 15