Symmetry

1. symmetry

2. Today we are learning to: • What is symmetry? • Line of symmetry. • Lines of symmetry for regular polygon. • Lines of symmetry for irregular polygon.

3. Symmetry When an object is divided into two equal parts such that one part coincides with the other, then such an object is a symmetrical object.

4. Line of symmetry: If a shape is folded exactly in half such that one half overlaps on top of the other half, then the fold or line is said to be a line of symmetry. Horizontal Line of Symmetry No Line of Symmetry Vertical Line of Symmetry

5. Symmetry in nature

6. Symmetry in alphabet letters

10. Symmetry in letters

11. Line of symmetry for regular polygon: A polygon is said to be regular if all its sides are of equal length and all its angles are of equal measure. For example:

13. Line of symmetry for irregular polygon: Any polygon that is not a regular polygon. A polygon whose sides are not all the same length or whose interior angles do not all have the same measures.

14. Example of irregular polygon : Let us fold the rectangle as shown one half of the rectangle exactly overlaps the other half along the line of symmetry.

15. Now (rectangle does not overlap along its diagonal). So, this is not a line of symmetry.

16. Thank you.