Properties of 3D Shapes
What are the names of common 3D shapes?
- You should know the general names of prisms
- A prism is a 3D shape with the same cross-section throughout
- The cross-section of a cube is a square
- The cross-section of a cuboid is a rectangle
- You will also have to work with other prisms, such as triangular prisms or hexagonal prisms
- In these cases the exam question will make sure the shape of the cross-section is clear
- A cylinder is similar to a prism
- The cross-section of a cylinder is a circle
- A prism is a 3D shape with the same cross-section throughout
- You should know the names and properties of the different types of pyramids
- A pyramid has a flat base with sloping sides that meet at a point at the top
- A square–based pyramid has a square as its base
- Some pyramids have special names you should know
- A tetrahedron’s base is an equilateral triangle
- A cone is similar to a pyramid
- A cone has a circular base
- You should know the name and properties of a sphere
What are the properties of 3D shapes?
- 3D shapes have a number of faces, vertices and edges
- A face is a single surface of the 3D shape
- A vertex (plural, vertices) is a corner of the 3D shape
- An edge joins one vertex to another
- You should know the number and shape of the faces for the common 3D shapes
- A cube has 6 equal, square faces
- A cuboid has 3 pairs of rectangular faces
- A cylinder has 2 equal circular faces and 1 rectangular face (its curved surface)
- A triangular prism has 2 equal triangular faces and 3 rectangular faces
- If the triangular faces are equilateral then all of the rectangles will be equal
- If the triangular faces are isosceles then two of the rectangles will be equal
- A square-based pyramid has 1 square face and 4 equal triangular faces
- A tetrahedron has 4 triangular faces
- A sphere has 1 face; it is a ball-shape
Examiner Tip
- Remembering the properties of 3D shapes will help in particular with questions involving surface area