In geometry, two lines that are always equidistant (the same distance apart). Parallel lines, curves and planes never meet.

A quadrilateral whose opposite sides are parallel and consequently equal in length.

A systematic arrangement of numbers, shapes, values or other objects according to a rule.

A polygon with five sides and five interior angles. Adjective: pentagonal, having the form of a pentagon.

A fraction expressed as the number of parts per hundred and recorded using the notation %. Example: One half can be expressed as 50%; the whole can be expressed as 100%.

Noun: a line or plane that is at right angles (90 degrees) to another line or plane. Adjective: having this property.

The length of any circle divided by the length of its diameter is a constant called pi, which has the symbol below.

Pi is an irrational number. It has an infinite number of non-repeating decimal places. To 8 decimal places, pi is 3.14159265.

A format for representing statistical information using pictures. Suitable pictures, symbols or icons are used to represent objects. For large numbers one symbol may represent a number of objects and a part symbol then represents a rough proportion of the number.

Also known as pie graph. A form of presentation of statistical information - within a circle, sectors like the slices of a pie represent the quantities involved. The frequency or amount of each quantity is proportional to the angle at the centre of the circle.