Shapes
You need to know the properties of the different types of triangle and square. Circles always have a radius, a diameter, and a circumference. You also need to know about other polygons such as hexagons and pentagons.
The perimeter is the length of the sides of a shape, and the area is the surface area that it covers. You need to know how to work out how many lines of symmetry a 2D shape has.
The perimeter is the length of the sides of a shape, and the area is the surface area that it covers. You need to know how to work out how many lines of symmetry a 2D shape has.
2D Shapes
Triangles
Triangles have three sides. There are many different types of triangles:
Equilateral triangle
Equilateral triangle
- 3 equal sides
- 3 equal angles of 60°
Isosceles triangle
- 2 equal sides
- 2 equal angles
Scalene triangle
- No equal sides
- No equal angles
Right-angled triangle
- One of its angles is a right angle (90°)
Quadrilaterals
Quadrilaterals have four sides. Here are some special quadrilaterals:
Square
Square
- 4 equal sides
- 4 right angles
Rectangle
- 2 pairs of equal sides
- 4 right angles
Rhombus (squashed square)
- 4 equal sides
- Opposite sides are parallel
- Opposite angles are equal
Parallelogram (squashed rectangle)
- 2 pairs of equal sides
- Opposite sides are parallel
- Opposite angles are equal
Trapezium
- One pair of parallel sides of different lengths
Kite
- 2 pairs of equal sides next to each other
- No parallel sides.
Circles
Polygons
Polygons are shapes with many straight sides:
Pentagons have 5 sides:
- Regular polygons have equal angles and sides of equal length.
- Irregular polygons have sides of different lengths.
Pentagons have 5 sides:
Hexagons have 6 sides:
Heptagons have 7 sides:
Octagons have 8 sides:
3D Shapes
3D shapes have faces (sides), edges and vertices (corners). The exception is the sphere which has no edges or vertices.
Nets of 3D shapes
The net of a 3D shape is what it looks like if it is opened out flat. A net can be folded up to make a 3D shape.
There may be several possible nets for one 3D shape.
Here are some examples:
Net of a cube
There may be several possible nets for one 3D shape.
Here are some examples:
Net of a cube
Net of a cuboid
Net of a square-based pyramid
Net of a triangle-based pyramid