Maths Terms for 11-13 Yr Olds

1. A part to whole comparison. Example: Where £20 is shared between two people in the ratio 3:5, the first receives £7.50 which is 3/8 of the whole £20. This is his proportion of the whole.

2. If two variables x and y are related by an equation of the form y = kx, then y is directly proportional to x; it may also be said that y varies directly as x. When y is plotted against x this produces a straight line graph through the origin. If two variables x and y are related by an equation of the form y = then y is inversely proportional to x; it may be said that y varies inversely as x.

An instrument for measuring angles.

A 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.

In 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.