CK-12 Foundation
Ck 12: Interactive Geometry: 1.5 Quadrilaterals
Explore and measure a variety of quadrilaterals.
Louisiana Department of Education
Louisiana Doe: Louisiana Believes: Eureka Math Parent Guide: Time, Shapes, and Fractions as Equal Parts of Shapes
A guide to support parents as they work with their students with time, shapes, and fractions as equal parts of shapes.
McGill University
Ear Cutting for Simple Polygons: Introduction
This site gives the definitions for various polygon-related material.
AAA Math
Aaa Math: Finding the Fourth Angle of a Quadrilateral
An interactive site that instructs and demonstrates how to find the fourth angle of a quadrilateral. This site also has many links to other interactive lessons.
Wolfram Research
Wolfram Math World: Dodecagon
This MathWorld site discusses dodecagons, a 12 sided polygon, the site gives formulas, yet variables are not defined well, to find the meanings of these variables go to the regular polygon link. [Requires Java.]
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Naming Polygons and Polyhedra
This site gives you the prefixes for naming polygons and polyhedra.
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Polyhedrons
This in-depth paper examines the idea of convexity. Euclid's Elements, the first geometry textbook, assumed convexity without mentioning the term.
Vernet -Virtual Education Resources Network
Salon Hogar: Referencia Rapida De Formulas Geometricas
This site provides the user with a useful reference to different geometric forms, their elements, formulas, and areas. Entirely in Spanish.
The Math League
The Math League: Figures and Polygons: Nonagons
This site provides definitions and examples of the various types of polygons including nonagons.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Actividades Con El Geoplano Formula De Pick
This interactive activity will lead you to the formula that was discovered by G. Pick in 1899. Gather all the data obtained in each of the activities and make a connection between the interior points, the points on the edge and the area...
Doina Popovici
Math Play: 2 D Shapes Jeopardy
Review basic facts and properties of two-dimensional shapes in this interactive game.
Other
Polyhedra: The Five Platonic Solids
A brief site that includes some activities to understand the figures.
Other
Ic Teachers: Shapes: Triangles
Are you looking for a very basic website that will explain the basic properties of a triangle? Use this site to learn about the properties of equilateral triangles, isosceles triangles, right triangles,and scalene triangles. There are...
ClassFlow
Class Flow: Perimeter of Regular Figures
[Free Registration/Login Required] This elementary flipchart presents the concept of regular shapes and ways of measuring perimeter. It also explores the ratio of perimeter to side length that equals the number of sides.
ClassFlow
Class Flow: Polygons
[Free Registration/Login Required] This is a lesson on interior and exterior angles of polygons. This has an interactive piece as well as an assessment piece.
ClassFlow
Class Flow: Polygons
[Free Registration/Login Required] This flipchart defines a polygon and the classification of concave and convex polygons.
ClassFlow
Class Flow: Tangrams
[Free Registration/Login Required] In this flipchart, students use the interactive features in Activstudio to simulate translations and reflections using objects. Students develop and apply their understanding of geometric sense by...
ClassFlow
Class Flow: Area
[Free Registration/Login Required] This flipchart teaches students how to find the area of an irregular polygon.
ClassFlow
Class Flow: Area of Polygons
[Free Registration/Login Required] This flipchart provides students with notes and practice with using formulas for finding the area of triangles and quadrilaterals.
ClassFlow
Class Flow: Dissection Puzzles
[Free Registration/Login Required] If you like tangrams, you'll enjoy this flipchart. Dissect and arrange in different shapes all types of squares, triangles, and polygons.
NumberNut
Number Nut: Shapes, Symbols and Colors: Two Dimensional Shapes
Describes, with illustrations, the basic two-dimensional shapes students will encounter in elementary Math.
University of Cambridge
University of Cambridge: Nrich: A Cartesian Puzzle
This one page website lets you practice plotting points on the coordinate grid. See if you can find the missing coordinates to complete the shapes. When you are finished the solutions are only a click away.
University of Cambridge
University of Cambridge: Nrich: Transformation Tease
Follow the directions at this one page website. You will get lots of practice plotting points on the coordinate grid and experience with transformational geometry.
University of Cambridge
University of Cambridge: Nrich: Egyptian Rope
See how many different regular polygons you can make using the 12 knot Egyptian rope at this one page website. Check your solution right at the website.