M1: Geometry and measures

Area is the amount of space taken up by a surface or a 2-D shape. It is measured in squares with metric units mm², cm², m² and km².

The perimeter of a circle is the circumference. The shortest distance from the centre to the circumference is the radius. The line across the centre of a circle is the diameter.

Compound measures involve two or more different units. Examples of compound measures and their units include speed (km/h), heart rate (beats per minute), miles per gallon (mpg).

The metric system is used to measure the length, weight or volume of an object.

Reverse percentages involve working backwards through a calculation to find the original amount before a percentage change.

Circle theorems are properties that are true for all circles, regardless of their size. There are six theorems to learn and recognise.

A 2D shape is symmetrical if a line can be drawn through it and either side is a reflection of the other. You would call this the line of symmetry.

All 2-D shapes are flat. They can have any number of sides that meet up with no gaps.

3-dimensional shapes have faces, edges and vertices and can be viewed from different points.