Page 88 - Mathematics Coursebook

8.1 Recognising and describing 2D shapes and solids

8.1 Recognising and describing 2D shapes and solids

You need to be able to recognise and describe 2D shapes and solids.

!ese are some of the 2D shapes that you should know.
Quadrilaterals

square rectangle parallelogram rhombus kite trapezium

Triangles

scalene triangle isosceles triangle equilateral triangle right-angled triangle
You should be able to use the words sides, parallel, equal and angles
to describe 2D shapes.
Look at the rectangle to the right.
You can see that all the angles are right angles (90°).
You can also see that opposite sides are both equal in length and parallel.

!ese are the solid shapes that you should know.
Solid shapes are also
called 3D shapes,
as they have three
dimensions: length,
cube cuboid square-based pyramid triangular-based pyramid
width and height.

triangular prism cylinder cone sphere Vertices are corners
You should be able to use the words faces, edges of the shapes. Each
and vertices to describe solid shapes. corner is a vertex.
Look at the triangular-based pyramid to the right.
You can see that it has 4 faces, 6 edges and 4 vertices. The mathematical name
for a triangular-based
pyramid is tetrahedron.

Worked example 8.1

Write down the name of the shape that is described below.
a ‘I am a 2D shape. I have four sides that are all the same length. My opposite angles are the same size
but I have no right angles.’

a Rhombus The sides are the same length, so it could be a square or a rhombus. As the opposite
angles are not 90° it is not a square. Opposite angles are equal so it is a rhombus.

8 Symmetry 87