National Council of Teachers of Mathematics
Nctm: Figure This: Fire Hydrant
Discover how the geometric shape of an object directly relates to its usefullness in this math challenge from the NCTM Math Challenges for Families collection. A one page activity that you can print or download.
Texas Instruments
Texas Instruments: Triangle Inequalities
This activity will help students visualize the properties of triangles stated in the theorems. By dragging the vertices, the students can see that the properties hold regardless of the size of the triangles and which sides are the...
Writing Fix
Writing Fix: Shape "Monsters" at Night
Using Melanie Watt's book entitled Scaredy Squirrel at Night, this multi-day lesson allows students to apply information about Scaredy Squirrel's night time experiences and its fears as their final product model. Students will create...
CK-12 Foundation
Ck 12: Geometry: Equilateral Triangles
[Free Registration/Login may be required to access all resource tools.] In this lesson students apply the properties of equilateral triangles. Students examine guided notes, review guided practice, watch instructional videos and attempt...
CK-12 Foundation
Ck 12: Geometry: Equilateral Triangles
[Free Registration/Login may be required to access all resource tools.] This concept will teach students the properties of equilateral triangles and how to apply them to solve problems. Students examine guided notes, review guided...
CK-12 Foundation
Ck 12: Geometry: Quadrilaterals That Are Parallelograms
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to prove that a quadrilateral is a parallelogram given the properties of parallelograms.
Math Open Reference
Math Open Reference: Decagon (10 Gon)
Learn about decagons with this resource which offers detailed explanations, examples, and an interactive. Subjects covered include properties of decagons. Links to related topics.
Math Open Reference
Math Open Reference: Heptagon (7 Gon)
Learn about heptagons with this resource which offers detailed explanations, examples, and an interactive. Subjects covered include properties of heptagons and heptagonal coins. Links to related topics.
Mangahigh
Mangahigh: Shape: Quadrilaterals Inscribed in Circles
Determine the missing angle measures of quadrilaterals inscribed in circles.
Alabama Learning Exchange
Alex: What Do We Have in Common?
This inquiry lesson explores the definitions of quadrilaterals and the properties of the diagonals of quadrilaterals to classify quadrilaterals. Students will work cooperatively to justify conclusions. This lesson plan was created by...
Maths Challenge
Maths challenge.net: Inscribed Rectangle
This is a proof problem, considered a "three star" geometry problem requiring knowledge of proofs and properties of circles to solve this equal area of inscribed polygons problem.
University of Cambridge
University of Cambridge: Nrich: Logo Programming Overlapping Polygons
Using this Logo Program you can experiment with different values for N in the procedure and see the changes in the results.
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...
Doina Popovici
Math Play: 2 D Shapes Jeopardy
Review basic facts and properties of two-dimensional shapes in this interactive game.
Cuemath
Cuemath: Angle Sum Theorem
Explore the world of the angle sum theorem in this mini-lesson. Provides a definition and solved examples that help with understanding their properties. Includes practice questions with answers.
Other
Bright Productions Web Designs: Shape Game
You will enjoy this shape game. It tells you the name of a shape and all you have to do is click on the correct shape. If you get confused you can have another try.
Alabama Learning Exchange
Alex: Quadrilaterals
This is an inquiry lesson used to review Algebra 1 objectives by applying them to geometry concepts. Students explore the properties of quadrilaterals and classify them by definition. This lesson can be use in geometry classes. Students...
Curated OER
Ic Teachers: Shapes: Polygons
The properties of the four different types of polygons--pentagons, hexagons, heptagons, and octagons--are discussed here. Some practice questions are also given to test your knowledge.
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...
Math Open Reference
Math Open Reference: Kite
Learn about kites with this handy reference guide. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.
Shodor Education Foundation
Shodor Interactivate: Lesson: An Introduction to Quadrilaterals
Quadrilaterals-parallelograms, rectangles, and trapezoids-are thoroughly introduced in this lesson plan for upper elementary and middle school students. Lots of resources are linked to it to help support the teacher and students....
Illustrative Mathematics
Illustrative Mathematics: G C Right Triangles Inscribed in Circles I
This task provides a good opportunity to use isosceles triangles and their properties to show an interesting and important result about triangles inscribed in a circle with one side of the triangle a diameter. The fact that these...
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: Count the Trapeziums (Trapezoids)
The challenge at this one page website, is to see how many trapezoids (British-trapeziums) you can find in the figure. When you have your results, you can easily check it right at the website.