OCR GCSE Mathematics key terms

An angle greater than 0° but less than 90°.

Sides or angles next to one another and sharing a vertex or side.

Angles next to one another that share a vertex and a boundary line without overlapping.

The side of a right-angled triangle next to the chosen acute angle, excluding the hypotenuse.

A connected sequence of mathematical statements used to justify a conclusion.

A mathematical statement made from numbers, letters and operations, without an equals sign; for example, $5n+2$.

A fraction containing one or more variables in its numerator or denominator.

An algebraic argument that establishes that a claim must be true in every case covered by it.

Angles lying between two parallel lines and on opposite sides of a transversal; they are equal.

The circle theorem stating that the angle between a tangent and a chord through the point of contact equals the angle subtended by that chord in the opposite segment.

The amount of turning between two rays that meet at a vertex, measured in degrees.

An angle formed at the centre of a circle by two radii.

An angle with its vertex on a circle and its sides meeting the circle at two other points.

A line that divides an angle into two equal angles; its points are equidistant from the two arms of the angle.

An angle formed by lines from a point on the circumference to the two endpoints of an arc or chord.

The direction opposite to the movement of the hands of a clock.

The symbol $\approx$, meaning “is approximately equal to”. It is used when two values are close but not necessarily identical.

A value read from a graph that is close to the exact value but may be limited by the graph's scale and drawing accuracy.

A value close to an exact value, chosen to make a calculation easier or to show its likely size.

A section of a circle’s circumference between two points.

The amount of surface enclosed by a two-dimensional shape, measured in square units.

The area enclosed by a circle, calculated using $A=\pi r^2$.

The multiplier that changes an area, including a surface area, from one similar shape to the corresponding area of another.

The region between a graph and the horizontal axis over a specified interval. Its contextual meaning depends on what the axes measure.

A sequence with the same difference between each pair of consecutive terms.

A sequence in which the difference between each term and the next is constant.

An arrangement from the smallest value to the largest value.

A line that a curve gets closer to without reaching. A vertical asymptote marks an x-value where the curve is undefined.