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6.1 - Solid Shapes & 6.2 - Spatial Relationships We’re going to talk about 6.1. Please open a geometry book The basics ♥ Polygon – 2 space ♥ Polyhedron = 3 space ♥ Polyhedra or Polyhdedrons = plural ♥ A Polyhedron is a closed figure, made up of polygons. ♥ Parts of a polyhedron: ♥ Faces – these are the polygons ♥ Edges – where the polygons intersect & form a line ♥ Vertices – “corners” – the point where more than two polygons intersect. edge face = Vertex face face edge edge face Regular Polyhedra (remember ‘regular’ means all sides have the same length and all angles have the same measure) A regular Polyhedra is composed of congruent regular polygons as faces AND has the same number of faces meeting at each vertex. Can you think of a regular polyhedron? DRAWING PRACTICE!! ♥ Let’s learn how to draw a cube. 1. Draw a square. 2. Draw a congruent square, up and to the right. Notice 4 pair of parallel lines 3. Connect the vertices TADA!! There are 5 convex, regular polyhedra and they are named by the number of faces they have. Platonic Solids NAME FACES MADE OF Tetrahedron 4 Triangles Hexahedron 6 Squares Octahedron 8 Triangles Dodecahedron 12 pentagons Icosahedron 20 Triangles LOOKS LIKE NETS A net is a 2D pattern that, when put together, forms a 3D polyhedron. Assignment Surface area worksheets (pg numbers at the bottom are 118-122)