Texas Instruments
Texas Instruments: What's the Angle?
Students discover properties of interior and exterior angles of convex polygons using the TI-89 and Geometer's Sketchpad.
Math Is Fun
Math Is Fun: Properties of Regular Polygons
Find a definition of regular polygon, and learn how to calculate the internal angle, external angle, and number of diagonals of a regular polygon. Also, learn how to find the area of regular polygons.
CK-12 Foundation
Ck 12: Elem Math: Identifying the Properties of Squares
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on identifying the properties of squares.
CK-12 Foundation
Ck 12: Elem Math: Identifying the Properties of Rectangles
[Free Registration/Login may be required to access all resource tools.] Students watch a video tutorial and attempt practice problems on identifying the properties of rectangles.
Wolfram Research
Wolfram Math World: Acute Triangle
This MathWorld site gives a short discussion on acute triangles with links to related terms and topics. The site offers a discussion on the least number of acute triangles to compose various polygons, and a discussion on the relationship...
Houghton Mifflin Harcourt
Holt, Rinehart and Winston: Homework Help Independent Practice: Polygons
Get independent practice working with polygons and their characteristics. Each incorrect response gets a text box explanation and another try. Correct responses are confirmed.
Math Open Reference
Math Open Reference: Interior Angles of a Parallelogram
Learn about the interior angles of a parallelogram with this helpful reference tool. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
The Math League
The Math League: Figures and Polygons
This website has basic definitions for most polygons, regular and irregular.
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.
Mathigon
Mathigon: Geometry: Angles and Polygons: Drawing Triangles
This lesson focuses on the Triangle Inequality, when the sum of the lengths of any two sides of a triangle is greater than the length of the third. When this happens, the three sides cannot form a triangle.
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...
University of Regina (Canada)
University of Regina: Math Central: Lesson: Mr. Z's 5 Minute Game of Geometric Pandemonium
Students make a series of geometric drawings of points, obtuse angles, rays, polygons, and the like. Each child is given one but not allowed to show anyone else. The drawing is then taped to the back of the child in front of them. The...
Other
Antonio Gutierrez: Geometry From the Land of the Incas
Discovering the properties of constructions, seeing proofs in action, and viewing problems come to life here with this wonderful use of technology in the classroom. Single steps are explained and illustrated one at a time so that the...
Mangahigh
Mangahigh: Shape: Quadrilaterals Inscribed in Circles
Determine the missing angle measures of quadrilaterals inscribed in circles.
Khan Academy
Khan Academy: Quiz: Inscribed Quadrilaterals
Use the fact that opposite angles in an inscribed quadrilateral are supplementary to solve a few problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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...
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...
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 learners. Lots of resources are linked to it to help support the teacher and students....
CK-12 Foundation
Ck 12: Inscribed Quadrilaterals in Circles
[Free Registration/Login Required] Students will explore quadrilaterals inscribed in circles with this interactive activity. Click 'Challenge Me' to answer a practice question.
CK-12 Foundation
Ck 12: Geometry: Inscribed Quadrilaterals in Circles
[Free Registration/Login may be required to access all resource tools.] Learn about the Inscribed Quadrilateral Theorem and solve problems involving quadrilaterals inscribed in circles.