Eduqas GCSE Mathematics key terms

A ratio comparing a length on a drawing or map with the corresponding actual length, using the same units. For example, $1:100$ means one unit on the drawing represents 100 of those units in reality.

A root that is a real number, so it can be represented on the number line. Negative numbers have real odd roots but no real even roots.

One divided by a non-zero number or expression. The reciprocal of $x$ is $1/x$.

The function $y = 1/x$, defined for $x \neq 0$, which gives the multiplicative inverse of each input.

A graph of a function of the form $y=\frac{k}{x}$, where $k$ is a non-zero constant and $x\ne0$.

A quadrilateral with four right angles.

An equation that defines a term using one or more earlier terms of a sequence.

A decimal in which a digit or block of digits repeats forever, such as $0.\overline{24}=0.242424\ldots$.

The quantity used as the basis of a percentage calculation, representing 100%.

A transformation that produces a mirror image across a line, with corresponding points at equal perpendicular distances from that line.

The property of a shape that maps exactly onto itself when reflected in a mirror line.

A polygon with all sides equal in length and all interior angles equal in size.

The proportion of trials in which an event occurs: $\frac{\text{number of times the event occurs}}{\text{total number of trials}}$. It is also called experimental probability.

A sample that reflects the relevant characteristics of the population closely enough to support conclusions about it.

The single vector representing the overall movement produced by adding vectors.

The bearing for travelling in the opposite direction along the same line; it differs from the original bearing by $180^\circ$.

A calculation that finds an original amount from its value after a percentage change, by dividing by the change multiplier.

A quadrilateral with four equal sides.

Right angle–Hypotenuse–Side: two right-angled triangles are congruent if their hypotenuses and one other pair of corresponding sides are equal.

The right angle–hypotenuse–side test for congruence: two right-angled triangles are congruent if their hypotenuses and one corresponding pair of other sides are equal.

An angle of exactly $90^\circ$, usually marked with a small square.

A triangle with one angle of $90^\circ$. Its longest side, opposite the right angle, is the hypotenuse.

A solid with matching, parallel polygonal end faces and an unchanged cross-section along its length. In a right prism, the edges joining the end faces are perpendicular to them.

A value of the variable that makes an expression equal to zero; for example, a root of $f(x)$ satisfies $f(x)=0$.

A transformation that turns a shape through an angle about a fixed point called the centre of rotation.

The property of a shape that maps exactly onto itself after a rotation of less than a full turn about its centre.

Replacing a number with a nearby value at a chosen degree of accuracy.

A selected part of a population from which data is collected.