Math Is Fun
Math Is Fun: Regular 2 D Shapes
This tutorial provides illustrations for regular 2-D shapes as well as a definition for polygons and for regular polygons.
Calculator Soup
Calculator Soup: Regular Polygon Calculator
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.
PBS
Pbs Mathline: Mirror, Mirror Lesson Plan [Pdf]
Determine which regular polygons tessellate by using mirrors. Printable lesson plan.
Analyze Math
Analyze Math: Polygons Problems
Here are four problems about the area of a regular polygon. Start by finding the area of a hexagon inscribed in a circle of radius 10, and end by proving that as the number of sides of the polygon increases, the area of the polygon...
Analyze Math
Analyze Math: Rotation Symmetry of Regular Polygons
An applet is used to investigate the rotation symmetry of regular polygons.
CK-12 Foundation
Ck 12: Geometry: Exterior Angles in Convex Polygons
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to calculate exterior angles of regular polygons. Students examine guided notes, review guided practice, watch instructional videos...
CK-12 Foundation
Ck 12: Geometry: Perimeter and Area Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide looks at the definitions and units for perimeter, area, and circumference, and at the perimeter and area of different shapes, including regular...
PBS
Pbs Mathline Lesson Plan: Struts'n Stuff [Pdf]
Incorporating concepts in algebra, number sense, patterning, data collection, and geometry, this lesson engages students in various hands-on activities to explore the relationship between regular polygons and the number of diagonals...
CK-12 Foundation
Ck 12: Geometry: Interior Angles in Convex Polygons
[Free Registration/Login may be required to access all resource tools.] Find the sum of the interior angles of a convex polygon.
Oswego City School District
Regents Exam Prep Center: Exterior Angles of Polygons
This site explains what the measure of the sum of exterior angles is for any polygon, and shows how to find the measure of individual exterior angles for regular polygons with a drawn example.
Mathigon
Mathigon: Geometry: Polygons and Polyhedra: More on Polyhedra
This lesson focuses on polyhedra other than the platonic solids; these include an Archimedean solid, a polyhedron made up of different kinds of regular polygons, that looks the same from every direction. There are 13 different...
Mathigon
Mathigon: Geometry: Polygons and Polyhedra: Platonic Solids
A Platonic solid is a polyhedron made up of only one kind of regular polygon, that looks the same from every direction. (In other words, the same number of faces meet at every vertex.) There are only five different Platonic solids:...
PBS
Pbs Mathline Lesson Plan: Mirror, Mirror [Pdf]
The goal of this PBS lesson is for students to apply spatial reasoning, problem solving, and critical thinking skills to assess which regular polygons will tessellate. A detailed lesson plan that includes related worksheets, lesson...
Other
Visnos: Polygons
Create regular and irregular polygons and determine the angles and side lengths with this interactive exercise. Use Safari or Chrome browser.
Louisiana Department of Education
Louisiana Doe: Louisiana Believes: Eureka Math Parent Guide: Geometry and Measurement Word Problems
A guide to support parents as they work with their students in geometry and measurement word problems.
ClassFlow
Class Flow: Segments and Polygons
[Free Registration/Login Required] This flipchart reviews segments, parallel and perpendicular lines and then introduces polygons including quadrilaterals. It has many real world examples of shapes and includes Activote assessment.
Texas Instruments
Texas Instruments: Figuring Areas
In this activity, students find the area of regular polygons using a summation approach and compare the summations with area calculated by Cabri Geometry Application. They also examine patterns of finding area and perimeter as the number...
Math Is Fun
Math Is Fun: Interior Angles of Polygons
Learn what an interior angle of a polygon is and how you can calculate their value in triangles, quadrilaterals, and pentagons. Includes a chart that overviews the "general rule" for determining the sum of internal angles in any polygon...
Curated OER
Nova Scotia Dept. Of Education: Mathematics 8: Geometry Diagrams
A collection of diagrams that complement Mathematics 8, a Grade 8 Math text, have been posted here. The diagrams were created using The Geometer's Sketchpad,
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.
PBS
Pbs: Mathline: Tessellations Wow! [Pdf]
An integrated geometry lesson on spatial sense in which students identify and use different shapes to create a tessellation. "Through a variety of modalities such as writing, music, art, poetry, and literature, students are introduced to...
Shodor Education Foundation
Shodor Interactivate: Lesson: Geometry in Tessellations
This upper elementary and middle school lesson plan explores tessellations and their geometric properties. Plenty of interactive support is available for students. Lots of resources for teachers to use.
University of Cambridge
University of Cambridge: Nrich: Where Are They?
Test your logic, polygon properties, and pattern recognition skills working on this challenge. Solution included.