#### Transcript Symmetry (Planes of)

One Line of Symmetry Vertical lines of symmetry Horizontal lines of symmetry Diagonal lines of symmetry 1 LoS 2 Lines of Symmetry 2 LoS The Rectangle Problem Rectangle A rectangle has only 2 lines of symmetry and not 4 like the square To see this consider the following: Half a rectangle Mirror Line The Rectangle Problem A rectangle has only 2 lines of symmetry and not 4 like the square To see this consider the following: A reflection in the diagonal would produce a kite! Half a rectangle Mirror Line 3 LoS 3 Lines of Symmetry 4 LoS 4 Lines of Symmetry 5 Lines of Symmetry 5 LoS 6 LoS 6 Lines of Symmetry Regular Polygons Equilateral Triangle Square Regular Pentagon Regular polygons have lines of symmetry equal to the number of sides/angles that they possess. Regular Hexagon Regular Octagon Regular How many lines of symmetry for each shape? 4 3 6 Mix 1 5 8 How many lines of symmetry for each shape? 6 5 3 Mix 2 4 5 How many lines of symmetry for each shape? 2 2 5 3 Mix 3 4 How many lines of symmetry for each shape? Mix 4 6 2 1 2 4 1 How many lines of symmetry for each shape? 1 2 4 Mix 5 5 3 How many lines of symmetry for each shape? 8 4 6 1 1 Mix 6 Plane Symmetry Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A Cuboid A Cuboid has 3 planes of symmetry Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A Cuboid A Cuboid has 3 planes of symmetry Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A Cuboid A Cuboid has 3 planes of symmetry Cuboid 3 Planes of symmetry Can you explain why the plane shown is not a plane of symmetry? This is similar to the situation for the rectangle which does not have a line of symmetry through its diagonal. Reflection through the diagonal produces a kite. No Diagonal Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A square based prism A square based prism has 5 Planes of symmetry Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A square based prism A square based prism has 5 Planes of symmetry Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A square based prism A square based prism has 5 Planes of symmetry Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A square based prism A square based prism has 5 Planes of symmetry Plane Symmetry A plane of symmetry divides a three dimensional shape into two congruent halves that are mirror images of each other. A square based prism A square based prism has 5 Planes of symmetry Square based prism 5 Planes of symmetry The 9 Plane Symmetries of the Cube Cube Triangular Based Prisms An isosceles triangular based prism has 2 planes of symmetry. Triangular Isos Triangular Based Prisms An isosceles triangular based prism has 2 planes of symmetry. Triangular Based Prisms An isosceles triangular based prism has 2 planes of symmetry. Triangular Based Prisms An equilateral triangular based prism has four planes of symmetry. Triangular Equilateral Triangular Based Prisms An equilateral triangular based prism has four planes of symmetry. Triangular Based Prisms An equilateral triangular based prism has four planes of symmetry. Triangular Based Prisms An equilateral triangular based prism has four planes of symmetry. Triangular Based Prisms An equilateral triangular based prism has four planes of symmetry. Pyramids A rectangular based pyramid has 2 planes of symmetry. Pyramids Pyramids A square based pyramid has 4 planes of symmetry. Pyramids Regular Tetrahedron: 6 planes of symmetry State the number of planes of symmetry for each shape 1 Questions2 6 4 3 2 1 5 Infinite 6 1 5 8 7 4 9 3 2