AQA GCSE Mathematics key terms

A change in which the same multiplier is applied to every value, so the quantities remain in a constant ratio.

The symbol $\propto$, meaning “is proportional to”. It must be replaced by an equals sign and a constant of proportionality before values are calculated.

A solid with a polygonal base and triangular faces that meet at one vertex.

The rule $a^2+b^2=c^2$ for a right-angled triangle, where $c$ is its hypotenuse.

One of the four regions formed by the $x$-axis and $y$-axis.

An equation that can be written as $ax^2+bx+c=0$, where $a$, $b$ and $c$ are constants and $a\ne0$.

A polynomial expression whose highest power of the variable is 2, usually written in the form $ax^2+bx+c$ where $a\ne0$.

A function whose highest power of the variable is 2, usually written in the form $y=ax^2+bx+c$, where $a\ne0$.

An inequality containing a squared variable, such as x² − 4 < 0.

A sequence whose nth term can be written in the form $an^2+bn+c$, where $a$, $b$ and $c$ are constants and $a\ne0$.

A four-sided polygon.

The number or expression beneath a root sign; in $5\sqrt7$, the radicand is $7$.

The distance from the centre of a circle to its circumference.

A process is random if its individual result cannot be predicted with certainty, even when the chances of its possible results are known.

The greatest value minus the least value; it measures the overall spread of a data set.

How much one quantity changes for each unit change in another quantity.

Money earned per unit of work, such as pounds per hour.

A comparison of quantities by division, written using a colon, such as $2:5$.

To rewrite a fraction with no surd in its denominator without changing its value.

Rewriting a fraction so that its denominator contains no surd while keeping its value unchanged.

One of the equal-sized units represented by the numbers in a ratio.

A comparison of a length on a drawing with the corresponding real length, expressed using the same units, such as 1 : 25 000.

A graph that represents quantities from a practical situation, with each axis showing a variable and usually its unit.

Rewriting a formula without changing the relationship it represents.

The number obtained by dividing 1 by a non-zero value; the reciprocal of $x$ is $\frac{1}{x}$.

A function involving division by the variable; the required basic reciprocal function is $y=\frac{1}{x}$, where $x\ne0$.

A relationship of the form $y=\frac{k}{x}$, where $k$ is constant and $x\ne0$; equivalently, $xy=k$.

A rule such as $P_{n+1}=kP_n$ that defines each term using an earlier term.