This site is all about inverse tangents. The site includes a definition, color graphs, formulas, and many links to related terms.

A site on inverse trigonometric functions. Contains a definition, a chart showing functions and their domains, formulas, and many links.

This math site explains what it means for a number to be irrational and names various persons who have proven the irrationality of some numbers, the site also gives several numbers who are thought to be irrational yet have not been proven to be irrational.

This MathWorld site gives Euclid's definition of a line, properties of lines, common terminology, and algebraic representations of lines and their distinctive parts in a cartesian system. The site then goes into detail of different line relations.

This site defines the term "locus" as it is used in mathematics and gives an example of the locus as a set of points equal distance from a point in two and three dimensional space.

This MathWorld site gives a visual description of dilation and the different kinds of dilation in a similarity transformation.

A definition for similar figures, directly similar, and inversely similar figures in Mathematics. Provides pictures to aid understanding.

Gives a detailed overview of hexagons, particularly of regular hexagons. Be sure to use the links for unfamiliar notation or variable representation. This site gives formulas for inner radius, circumradius, parameter, and area of a regular hexagon, and much more.

Explains how to perform matrix multiplication, including how to perform products on two block matrices. Also has links to related topics.

Defines vector addition and gives the algebraic notation for adding vectors. Includes a graphic and links to additional information.

This site gives graphs of logarithmic functions and pays particular attention to base 10 and base e (natural logarithm). The site explains how to change bases, the importance of the natural logarithm in calculus, incorporating the complex numbers with natural logarithms, the Taylor Series for the natural log and more.

A definition for parallel lines in two-dimensional and three-dimensional Euclidean space. The site also gives reference to skew lines and explains the difference between skew and parallel lines in three-dimensional space.

MathWorld's definition of a perpendicular bisector, with illustrations to show the different uses of the perpendicular bisector.

This MathWorld site defines postulates, and explains how and where they are used in mathematics. The site has numerous links to related terms.

This is a resource for many topics in probability and statistics. Click on the topic of your choice for an explanation. The sites you will be linked to are quite extensive. A degree of higher-level math is necessary for understanding some of these sites.

This site provides extensive information about Pythagorean triples. It begins by explaining its relation to the Pythagorean theorem, and then gives ways to generate Pythagorean triples using relatively prime numbers and Fibonacci numbers.

This site gives an overview of rational numbers, gives interesting facts about the rational numbers including countability and probability of a rational numbers denominator being even. The site also contains related links.

This site from MathWorld.com offers extensive information on right triangles. The site contains information on numerous characteristics of right triangles, including constructing similar inscribed triangles, altitudes, Pythagorean triplets, and much more.

Describes how a scalar can be multiplied to a vector and shows this using diagrams. Site also contains related links, graphs, and pictures.