1. Line Symmetry Slideshow 34, Mathematics Mr Richard Sasaki Room 307

2. Objectives Recall shape names and properties Learn the meaning of “line symmetry” Understand how to find lines of symmetry

3. Edges, Vertices and Faces Vertex (plural: vertices) Edge Face – Used more with 3D objects

4. Shape names Let’s review the shape names…

5. Triangles The four special types of triangles are… AN EQUILATERAL TRIANGLE. AN ISOSCELES TRIANGLE. A SCALENE TRIANGLE. A RIGHT- ANGLED TRIANGLE WHAT DO THE DASH (‘-’) SYMBOLS MEAN? THAT THESE LINES ARE THE SAME LENGTH AS ONE ANOTHER. THAT THE LINES ARE PARALLEL.

6. Quadrilaterals There are many types of special quadrilaterals. A SQUARE. A RECTANGLE. A RHOMBUS. A KITE. A PARALLELOGRAM. A TRAPEZIUM.

7. Line Symmetry What is line symmetry? Line symmetry is a line of reflection. On both sides of this line, both pieces appear the same, reflected. If we can fold the shape into two identical sections (when folded), this fold is the line of symmetry.

9. Lines of Symmetry We now should know a bit about lines of symmetry. It’s important to be able to visualise what shapes have what lines of symmetry without folding them or using a mirror. Complete the last worksheet and state how many lines of symmetry each shape has.

10. 3 3 3 4 4 4 4 4 4 5 6 7 8 3 1 0 4 2 2 1 1 / 0 0 5 6 7 8

11. Regular Shapes What can we say about the number of lines of symmetry for regular shapes? It is equal to the number of edges!