This is a long webpage, listing lots of geometry resources. I have grouped them by the subtopics in geometry, so please see the following list. Each topic has resources that fit many grade levels.
Geometry Bridge
An interactive review lesson on types of angles, types of triangles, angle sum of a triangle, and the Pythagorean Theorem, for 5th-7th grade students. You get to build a bridge! mysite.verizon.net/vzex2lij
Math Mammoth Geometry 1
A self-teaching worktext for 4th-5th grade that covers angles, triangles, quadrilaterals, symmetry, solids, perimeter, area, volume, and more. The book uses a lot of "learn by drawing" exercises.
Available as an affordable download ($7.00), and also as a printed copy.
Angles
Practice your knowledge of acute, obtuse, and alternate angles, plus relationships between angles such as vertical, adjacent, alternate, same-side, and corresponding. www.shodor.org/interactivate/activities/Angles
MB-Ruler - a triangular ruler for the computer screen
MB-Ruler is a software that helps you to measure distances and angles on the computer screen, such as distances on a map or angles in any image. It has a ruler and a protractor, which are almost transparent over the image you are working with. www.markus-bader.de/MB-Ruler
Math Mammoth Geometry 1
A self-teaching worktext for 4th-5th grade that covers angles, triangles, quadrilaterals, symmetry, solids, perimeter, area, volume, and more. The book uses a lot of "learn by drawing" exercises.
Available as an affordable download ($7.00), and also as a printed copy.
Paper Models of Polyhedra
This site provides hundreds of free printable paper models for various solids, including platonic solids, pyramids, and lots of polyhedra. Some are available as colored versions also. www.korthalsaltes.com
Geometry Volume/Surface Area Quiz from ThatQuiz.org
An online quiz, asking either the volume or surface area of cubes, prisms, spheres, cyliners, or cones. You can modify the quiz parameters to your liking, for example to omit some shapes, solve only for volume or surface area, or instead of solving for volume/surface area, you solve for an unknown dimension (side or radius) when the volume or surfare area is given. www.thatquiz.org/tq-4/?-j3vu0-lc-m2kc0-na-p0
Dome Book
Instructions for building geodesic play-domes out of cardboard or plastic. The site includes two free printable dome models and a book that contains plans for constructing nine kinds of domes in any size desired. www.domebook.com
Math Mammoth Geometry 2
A self-teaching worktext for 6th-7th grade that covers angle relationships, classifying triangles & quadrilaterals, angle sums, similar figures, congruent transformations, area, pi, volume, surface area, constructions, and unit conversions. The book uses a lot of "learn by drawing" exercises.
Available as an affordable download ($5.80), and also as a printed copy.
Math Mammoth Geometry 2
A self-teaching worktext for 6th-7th grade that covers angle relationships, classifying triangles & quadrilaterals, angle sums, similar figures, congruent transformations, area, pi, volume, surface area, constructions, and unit conversions. The book uses a lot of "learn by drawing" exercises.
Available as an affordable download ($5.80), and also as a printed copy.
Circle Tool
An applet that allows you to investigate how the area and circumference of a circle compare to its radius and diameter in the Intro and Investigation sections and then hone your skills in the Problems section.
You can drag the radius to various lengths, and the click the "Add to Table" button to record the data in the table. You can also examine the ratios of any two measures, and make a graph of the data
illuminations.nctm.org/ActivityDetail.aspx?ID=116
Rolling circle illustrating Pi
This is a short animation where a circle with diameter 1 rolls on a number line one complete roll. Of course having rolled once around its circumference, it now lands at 3.14 or Pi. http://i.imgur.com/dsCw0.gif
Absorb Mathematics
Absorb Mathematics is an excellent interactive course written by Kadie Armstrong, a mathematician. The lessons in it contain interactivity, explanations, and quiz questions. The course concentrates on geometry and trigonometry but includes a few other topics as well. While most of the content is accessible by a fee only, some lessons are available as free samples.
Maisonet Math
Worksheets and online quizzes on a variety of geometry (and other) topics. Look for the links in the left sidebar for Angles, Area, Circumference, Geometry, Transformations, and Volume. www.mrmaisonet.com
Let's Practice Geometry
Lots of free geometry worksheets for high school. Includes worksheets for the basics, Pythagorean Theorem, perimeter, area, and volume, angles, triangle theorems, similarity and congruence, logic, proofs, trig, polygons, and circles.
www.letspracticegeometry.com
Geometry worksheets at AGMath.com
Hundreds of free PDF worksheets for high school geometry topics, loosely based on the "Discovering Geometry" textbook by Michael Serra. Compiled by Jason Batterson, an 8th grade, algebra, geometry, and MathCounts teacher. AGmath.com/1973.html
Books
Math Mammoth Geometry 1
A textbook/workbook together for grades 3-5, written by the owner of this site. You will learn geometry by drawing. Topics covered include angles, rectangles, parallelograms, polygons, circles, area, perimeter, and volume. Price: $7.00 download, $12.70 printed. www.mathmammoth.com/geometry_1.php
Math Mammoth Geometry 2
A textbook/workbook together for grades 6-7, written by the owner of this site. It continues the study of goemetry after Math Mammoth Geometry 1, continually emphasizing conceptual understanding, besides calculation-type exercises. Price: $5.80 download. www.mathmammoth.com/geometry_2.php
Geometry: A Guided Inquiry
An excellent choice for high school geometry. I've written an in-depth review of this book and of its supplement Home Study Companion - Geometry, latter by David Chandler.
Kiselev's Geometry / Book I. Planimetry
A famous Russian geometry book translated. Acclaimed for the clarity of exposition which makes the book accessible for 7th graders.
A High School First Course in Euclidean Plane Geometry
This is a high school geometry course by Charles Aboughantous. It is based on Euclid's five postulates and his most common theorems. It promotes the art and the skills of developing logical proofs. Practice problems are included at the end of each chapter in three groups: geometric construction problems, computational problems, and theorematical problems. The answers to the computational problems are included at the end of the book. The solutions manual of the book contains detailed solutions to all the problems in the book. It is free to home schooled students upon proof of purchase of the book. Samples are found at http://home.earthlink.net/~draboughantous/geometry.html
Kiselev's Geometry / Book I. Planimetry
A famous Russian geometry book translated. Acclaimed for the clarity of exposition which makes the book accessible for 7th graders.
Go Geometry
All things geometry: geometry theorems, huge list of geometry problems, presented with visual diagrams, geometric art, puzzles, dynamic geometry, and more. gogeometry.com
Knowhere
Discover how the structure of space determines the shape of things. Lessons about symmetry of polyhedra, space filling, how atoms pack together, structure of minerals. Also lessons about structural stability such as inbridges, beams, and buildings - basics of engineering. www.polymorf.net/knowhere.htm
Structured drill of multiplication tables—much more effective than random drill!
