year 8 maths

6G
Euler’s formula for three-dimensional solids
387
■ Pyramids are polyhedra with a base face and all other faces meeting at the same vertex point
called the apex. They are named by the shape of the base.
apex
Square
pyramid
Key ideas
■ Some solids have curved surfaces . Common examples include:
Cylinder Sphere Cone
■ A cube is a hexahedron with six square faces.
Example 10
Classifying solids
a
Classify these solids by considering the number of faces.
i ii iii
b Name these solids as a type of prism or pyramid (e.g. hexagonal prism or hexagonal pyramid).
SOLUTION
EXPLANATION
a i hexahedron The solid has six faces.
ii heptahedron
iii pentahedron
The solid has seven faces.
The solid has five faces.
b i rectangular prism It has two rectangular ends with rectangular sides.
ii pentagonal prism
iii square pyramid
It has two pentagonal ends with rectangular sides.
It has a square base and four triangular faces
meeting at an apex.
Cambridge Maths NSW
Stage 4 Year 8 Second edition
ISBN 978-1-108-46627-1 © Palmer et al. 2018
Cambridge University Press
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