1. GEOMETRY (HOLT 9-5) K. SANTOS Symmetry

2. A figure has symmetry if there is a transformation (change) of the figure such that the image coincides with the preimage (original image) Can you fold it onto itself exactly? Can you rotate it without anyone knowing? There are two types of symmetry: Reflectional Symmetry----folding Rotational Symmetry------spinning/rotating

3. Reflectional Symmetry (line symmetry) A figure has reflectional symmetry (line symmetry) if it can be reflected across a line so that the image coincides with the preimage. Fold the figure along the line of symmetry and the halves match up exactly Reflectional Symmetry—one half of the image is a mirror image of its other half The line of symmetry (axis of symmetry) divides the figure into two congruent halves.

4. Examples of Figures with Reflectional Symmetry

5. Examples of Letters with Reflectional Symmetry HELLO MATH STUDENTS ! Letters with reflectional (line) symmetry: H, E, O, M, A, T, U, D HELLO MATH STUDENTS! Letters with reflectional (line) symmetry: H, E, O, T, D

6. Rotational Symmetry (Radial Symmetry)

7. Examples of Figures with Rotational Symmetry

9. Point Symmetry