Here's a great geometry activity to display students' knowledge of the different types of triangles. Provides resources and adaptations to supplement this lesson. (To access this lesson plan, you must register with Crayola.com....

On this site a viewer can learn about the different types of triangles, and categorized by either angles or sides. Tutorials are also included for interior and exterior angles of triangles. A teacher resource page includes a lesson plan...

A list of geometry definitions and a matching activity.

Explore and learn about the features and properties of a right triangle in this lesson. Includes examples and practice questions.

Explore the world of the altitude of a triangle in this mini-lesson including its definition, altitudes in different types of triangles, formulae, some solved examples, and a few interactive questions for you to test your understanding.

Students will begin unit on quadrilaterals with basic overview of characteristics of parallelograms, rectangles, squares, rhombi, and isosceles and non-isosceles trapezoids. After the word wall is made, the teacher can use interactive...

In this activity, students investigate properties of triangles by randomly generating possible side lengths for triangles. They learn to determine if three line segments can form a triangle. They also learn to classify triangles as...

Practice identifying triangles by their side-lengths as equilateral, isosceles, or scalene. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.

Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.

The division of triangles into scalene, isosceles, and equilateral can be thought of in terms of lines of symmetry. Aligns with 4.G.A.3.

In this task, 8th graders are given the dimensions of two isosceles triangles and are asked to compare their areas. They must draw them and use the Pythagorean Theorem and the triangle area formula to solve the problem. Aligns with 8.G.B.7.

A computer simulation of viewing through various lengths of tubes at different distances. The simulation also has an exploration of focus questions. [Requires Java.]

Students can practice classifying triangles based on side lengths through a series of self-check exercises and timed learning games.

In this video segment from Cyberchase, Bianca injures her ankle while skateboarding and is confined to her bed. She has trouble reaching a few objects from her bed until her friend gives her a device made up of collapsible...

This site provides definitions of different types of polygons and figures.

This site gives a short interactive quiz which allows students to self-assess their understanding of the concept of triangles and angles.

[Free Registration/Login may be required to access all resource tools.] Recognize special right triangles and their properties.

[Free Registration/Login may be required to access all resource tools.] Apply the special properties of 45-45-90 right triangles.

[Free Registration/Login may be required to access all resource tools.] Apply the properties of trapezoids.

[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on classifying a triangle inside a composite figure.

[Free Registration/Login may be required to access all resource tools.] In this learning module, students are presented with a composite figure and must identify the types of triangles within it. An accompanying video demonstrates a...

[Free Registration/Login may be required to access all resource tools.] Classify triangles by side lengths and angle measures.

[Free Registration/Login may be required to access all resource tools.] Classify triangles by side lengths and angle measures.