An angle that measures less than 90° and more than 0°.

A number’s distance from zero. Distance is expressed as a positive value.

Used to determine the probability that event A or event B occurs or both occur. The rule is often written as:

P(A or B) = P (A) + P(B) – P(A and B

Two numbers who sum is 0.   

Amplitude is half the distance between the minimum and maximum values of the range of a periodic function with a bounded range.

Similar or corresponding in some respect.

Geometry based on the coordinate system (also known as coordinate geometry).

Explains data on the basis of deeper theoretical ideas with parameters that are empirically based.

If two angles of one triangle are equal to two angles of another triangle, then the triangles are similar.

A mathematical operation involving numbers. Usually refers to operations of addition, subtraction, multiplication, and division.

The way in which three or more numbers are grouped for addition or multiplication does not change their sum or product, respectively.

An asymptote is a line or curve that approaches a given curve arbitrarily closely.

Segments and lines added to existing figures. Auxiliary lines are usually added to allow us to prove something about the figure

A statement accepted to be true without proof.

Pairs of linked observations – may be numeric or categorical.