Wolfram Research
Wolfram Math World: Geometry
This MathWorld tutorial provides detailed overviews of the concepts and theorems associated with geometry. Most of the Math World sites are extensive and some require higher math knowledge to understand, links to terms and topics are...
Clark University
Clark University: Dave's Short Trig Course: Transformations of the Plane
Site that focuses on planar pattern and transformations within geometry. It also identifies different kinds of symmetry.
Math Is Fun
Math Is Fun: Lines of Symmetry of Plane Shapes
Looks at the lines of symmetry in different types of polygons. Includes ten practice questions. Each question is accompanied by an explanation of the answer.
Wikimedia
Wikipedia: Plane of Symmetry
This site from the free encyclopedia, Wikipedia, provides a basic definition for plane of symmetry. Links are given for additional information on related subjects.
Oswego City School District
Regents Exam Prep Center: Intuitive Notion of Line Symmetry and Plane Symmetry
Definitions are provided line of symmetry, line symmetry, and plane symmetry, and several nice examples are provided that illustrate these definitions.
Oswego City School District
Regents Exam Prep Center: Intuitive Symmetry: Point, Line, Plane, Rotational
Investigate the concept of symmetry at this test prep site. See detailed definitions and picture examples, answer the questions in the interactive practice pages, and do the classroom activity where learners use a digital camera to...
Texas Instruments
Texas Instruments: Reflecting a Triangle in the Coordinate Plane
In this activity, students use the drawing and measurement tools of Cabri Jr. to blend coordinate geometry with drawing tools. They visualize symmetry and reflect a point across the y-axis.
E-learning for Kids
E Learning for Kids: Math: Castle in the Clouds: Space: 2 D Shapes and Symmetry
Students will explore symmetry through a variety of learning games.
Khan Academy
Khan Academy: Symmetry of 2 D Shapes
Analyze various shapes according to their reflective and rotational symmetries. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
PBS
Pbs Mathline Lesson: Geometry, It's a Perfect Fit [Pdf]
This two-part geometry lesson plan has students identify, describe, and classify two-dimensional shapes. Students engage in hands-on activities including identifying shapes in the classroom, creating patterns with shapes, identifying...
Illustrative Mathematics
Illustrative Mathematics: G Co Seven Circles Ii
In this task, seven pennies are placed in a circle so that they are all touching one in the center and their neighbors. Learners are asked to find as many rigid motions of the plane as they can which are symmetries of this configuration...
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.
ClassFlow
Class Flow: Graph of an Equation
[Free Registration/Login Required] In 1637, Rene Descartes revolutionized the study of mathematics by joining its two major fields, algebra and geometry. With Descartes's coordinate plane, geometric concepts could be formulated...
Illustrative Mathematics
Illustrative Mathematics: G Co Reflections and Equilateral Triangles
Given an equilateral triangle, students are asked to explore its symmetries using rigid transformations of the plane. Aligns with G-CO.B.
National Council of Teachers of Mathematics
The Math Forum: Building Shapes
Based on building a hexagon, this activity from the Math Forum collection focuses on using different combinations of pattern blocks to create a hexagon. An online activity, pencil and paper method, literature connections, and a...