Basic 3D shapes Discussion of Nets Isometric projection Faces, edges and vertices Ex30.1 on the board
3D Symmetry Planes of symmetry Axis if rotational symmetry Ex 30.2 – 10 minutes
Plans and elevations A plan view is to look down from above An elevation is to look at an object from the front, back or side In reality the drawings are usually done to scale and contain dimensions. (arrows labelling lengths)
Surface area Consider every face of a 3D shape. These could be drawn as a 2D shape, which we could then find the area of (using our knowledge from a few weeks ago) Add up the area of each face for the total surface area. For example, a cuboid is made up of rectangles and squares
Volume of a cuboid The volume of a cuboid is found by multiplying all the lengths. You could consider this as finding the area of one end, then multiplying by the length. Ex30.4 – 10 minutes
Volume of a prism A prism is a 3D shape, which is continuous all the way through. Its volume is found by working out the area of the end face, and multiplying this by the length of the shape. Ex 30.5 Q1,2 and 3
Surface area of a prism Total surface area of a prism is found by adding up the area of each face. For example, a triangular prism is made up of 2 identical triangular faces and 3 rectangular ones.