PyramidA solid with a polygon as the base and one other vertex, the apex, in another plane. Each vertex of the base is joined to the apex by an edge. Other faces are triangles that meet at the apex. Pyramids are named according to the base: a triangular pyramid (which is also called a tetrahedron, having four faces), a square pyramid, a pentagonal pyramid etc. |
Pythagoras' TheoremIn a right-angled triangle, the square of the length of the hypotenuse is equal to the sum of the squares of the lengths of the other sides i.e. the sides that bound the right angle. |
QuadrantOne of the four regions into which a plane is divided by the x and y axes in the Cartesian co-ordinate system. |
QuadrilateralA polygon with four sides. |
QualitativeRelating to a quality or attribute. Used as an adjective to describe conclusions and explanations that use mostly words as opposed to numbers and equations (quantitative). |
QuantitativeRelating to a quantity or number. Used as an adjective to describe conclusions and explanations that use mostly numbers and equations as opposed to words (qualitative). |
QuartileWhere quantitative data is ranked in ascending order, the three quartile values (first, second and third) divide the data into four equal parts. The difference between the first and third quartiles, used as a measure of spread, is the interquartile range. The second quartile is also the median value. |
QuotientAnother word for the result of a division. Example: 5 is the quotient of 100/20. The number being divided, in this case 100, is sometimes known as the dividend. |
RadiusIn relation to a circle, the distance from the centre to any point on the circle. Similarly, in relation to a sphere, the distance from the centre to any point on the sphere. |
Random SampleIn statistics, a selection from a population where each sample of this size has an equal chance of being selected. |