In this mini-lesson, learn about obtuse triangles including the obtuse triangle definition, sides, properties, examples, and other fun facts related to it.

[Free Registration/Login may be required to access all resource tools.] This study guide reviews terminology for triangles, triangle properties, different types of triangles, and interior and exterior angle theorems.

This lesson plan provides students with an opportunity to practice drawing and measuring triangles and angles. It also shows pictures and gives definitions of each type of angle and triangle.

This site from the University of Saskatchewan provides an explanation of similar triangles, the Pythagorean theorem, and the distance between arbitrary points in a plane. Example problems for each of these concepts are provided.

Use this applet to show how the placement of the third vertex of a triangle affects the classification of that triangle.

Identify and compare shapes based on their attributes. Shapes include triangle types, quadrilateral types, pentagons, and hexagons. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video...

Explore full angles triangles with this handy reference guide. Provides a detailed definition and an interactive activity that enhances further explanation. Includes links to related topics.

Kindergarteners love to identify shapes in their environment. In order effectively do that, they must be able to recognize different shapes by their specific attributes. In this lesson kindergartners learn about different types of...