This geometry lesson defines equilateral, isosceles, and scalene triangles, and has a variety of exercises, including drawing exercises.

A list of geometry definitions and a matching activity.

Students learn abouT the Law of Reflection by constructing an equilateral triangle using graph paper, pencil, protractor, and a ruler and a "laser triangle" using a laser pointer and front-silvered mirrors.

Three circles are mutually tangent. Students are asked to find the total area of the circles plus the area inside where they meet. Students will need to know how to calculate the area of a circle, a sector of a circle, and an equilateral...

Learn about the properties of 2-D shapes: circles, triangles, polygons, and quadrilaterals. Includes information, video, and examples about each, with games and quizzes for reinforcement.

Practice problem worksheets are available for students needing to study basic terms relating to triangles and other math concepts.

This in-depth paper examines the idea of convexity. Euclid's Elements, the first geometry textbook, assumed convexity without mentioning the term.

[Free Registration/Login Required] Using this flipchart students learn to recognize and classify different triangles, including equilateral, isosceles and scalene. The teacher will use this lesson plan to review different types of...

Explore polygons with Wang, a ricksha puller. Answer his questions and he will give you a free ride!

This site provides definitions of different types of polygons and figures.

Remove four matches to the center of the square then repositions the other matches in such a way that the sum of them on each side is 11.

Learn about the Euler line with this handy reference guide. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.

In this task, seven pennies are placed in a circle so that they are all touching one in the center and their neighbors. The question is whether this will work with other equally-sized circles. Aligns with G-SRT.C and G-CO.C.10.

On this site students are instructed to locate different types of polygons on triangle grid paper. This page can be printed so that students can actually draw them. It also gives a definitions link for each polygon.

This University of St. Andrews site contains information on the life of Heron as well as his accomplishments.

Introduces the concept of regular polygons along with regular polygon examples, not regular polygons, irregular polygons, and area of a regular polygon. Check-out the solved examples for better understanding and try your hand at solving...

A problem with equilateral triangles and area to solve this "Shaded Hexagon" problem. Mathematical reasoning and triangle knowledge will be needed to solve the problem.

Based off of the hit television show NUMB3RS, this lesson has students examine a set of transformations to determine if certain properties (such as associativity and closure) exist for equilateral triangles. Students create tables of...

Do you need practice remembering or learning different geometry vocabulary words and definitions? The flash cards at this web site are for you! There is a link to a list of terms with definitions you can click if you want to see if you...

Do you need practice remembering or learning different geometry vocabulary words and definitions? This concentration game is the web site for you! There is a link to a list of terms with definitions you can click if you want to see if...

In this lesson, students learn to inscribe regular polygons inside a circle.

This site gives an explanation of Napolean's Theorem and gives several links to Napoleon's Theorem.

Use this calculator to calculate properties of a regular polygon. Enter any 1 variable plus the number of sides or the polygon name. Calculates side length, inradius, circumradius, area, and perimeter.

If art and math are both passions of yours, this project is meant for you! Spidrons are geometric forms made from alternating sequences of equilateral and isosceles (30 degrees, 30 degrees, 120 degrees) triangles. Spidrons were...