 # Algebra - 3rd Edition

## Chapter 13: Right Triangle Relationships

Some links are repeated for use with more than one lesson.

Please report broken links to Kathy Kral

### 13.1 Similar Triangles

http://www.math.com/school/subject1/lessons/S1U2L4GL.html
This site defines similar figures.

http://www.gcseguide.co.uk/similar_triangles.htm
This page gives a brief description of similar triangles.

### 13.2 The Pythagorean Theorem

http://www.cut-the-knot.org/pythagoras/index.shtml
This page defines the Pythagorean Theorem and has several proofs explaining it.

http://www.mathsisfun.com/pythagoras.html
This site explains the Pythagorean Theorem and has pictures showing the sides of a triangle.

### 13.3 Irrational Numbers and Radicals

This page contains an explanation of radicals, rational, and irrational numbers and had questions with interactive answers.

### 13.4 Special Right Triangles

http://www.onlinemathlearning.com/special-right-triangles.html
This site explains the special right triangles and tells the lengths of their sides.

http://www.regentsprep.org/regents/math/algtrig/ATT2/Ltri45.htm
NEW This page explains the 45-45-90 special right triangle.

http://www.regentsprep.org/regents/math/algtrig/ATT2/Ltri30.htm
NEW This page explains the 30-60-90 special right triangle.

### 13.5 Trigonometric Ratios

http://www.tpub.com/math1/20b.htm
This site defines what trigonometric ratios are, gives the six basic, and states their abbreviations.

http://mathsfirst.massey.ac.nz/Trig/TrigRatio.htm
This page stages the six most common trigonometric ratios and has an interactive triangle to practice deciphering one ratio from the other.