National Council of Teachers of Mathematics
The Math Forum: Triangle Formulas
Investigate the geometric definitions of triangles, focusing upon equilateral, isosceles, right, and scalene with detailed drawings and appropriate formulas for each. This site has links to more information on triangles.
Beacon Learning Center
Beacon Learning Center: Triangles Side by Side
This comprehensive web lesson describes how to classify triangles by their angle and side measurements. It provides real-world examples and exercises for students to practice the skill.
Oswego City School District
Regents Exam Prep Center: Angles and Triangles
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...
CK-12 Foundation
Ck 12: Elem Math: Classifying All Types of Triangles by Lengths of Sides
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on classifying triangles based on length of sides.
CK-12 Foundation
Ck 12: Elem Math: Classifying Triangles by Identifying the Number of Equal Sides
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on classifying triangles based on the number of equal sides.
CK-12 Foundation
Ck 12: Geometry: Triangle Classification Grades 8 10
[Free Registration/Login may be required to access all resource tools.] Classify triangles by side lengths and angle measures.
Quia
Ixl Learning: Types of Triangles
Brush up on your math skills relating to the types of triangles then try some practice problems to test your understanding.
CK-12 Foundation
Ck 12: Geometry: Triangle Classification Grade 7
[Free Registration/Login may be required to access all resource tools.] Classify triangles by side lengths and angle measures.
CK-12 Foundation
Ck 12: Geometry: Triangle Sum Theorem Grade 8
[Free Registration/Login may be required to access all resource tools.] Finding and understanding the angle measures of triangles.
CK-12 Foundation
Ck 12: Geometry: Triangle Classification Grade 8
[Free Registration/Login may be required to access all resource tools.] Classifying triangles by using angle measures and side lengths.
CK-12 Foundation
Ck 12: Geometry: Triangle Classification Grades 9 10
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to classify triangles based on their angles and sides.
PBS
Pbs Learning Media: Triangles: Targeted Math Instruction
Students will learn how to apply the properties and characteristics of all triangles to solve real-world problems and identify and use the unique characteristics of right, isosceles, equilateral, acute, obtuse, and scalene triangles.
Math Open Reference
Math Open Reference: Triangle Quiz
Students are assessed on different types of triangles. Definitions of the triangles are included.
McGraw Hill
Glencoe Mathematics: Online Study Tools: Triangles and Angles
This site gives a short interactive quiz which allows students to self-assess their understanding of the concept of triangles and angles.
Alabama Learning Exchange
Alex: A Triangle to Remember
This lesson will introduce students to different types of triangles by using a clip from the movie A Walk to Remember. They will take part in interactive tutorials to strengthen the concepts of classifying triangles. The students will...
Merriam-Webster
Merriam Webster: Dictionary Illustration: Types of Triangles
A labeled illustration of six different types of triangles.
Math Is Fun
Math Is Fun: Interactive Triangles
This is an excellent tool for students to explore how changes in the size of a triangle's sides or angles affect its appearance. Different types of triangles and angles are presented.
Math Planet
Math Planet: Pre Algebra: Triangles
Learn about the types of triangles by taking a look at an example and a video lesson.
Oswego City School District
Regents Exam Prep Center: Triangle Information
This Oswego City School District site from the Regents Exam Prep Center provides an explanation of the classifications of triangles both by sides and by angles. Pictures are also included.
Mocomi & Anibrain Digital Technologies
Mocomi: Types of Triangles
Explore the different types of triangles and other properties.
OER Commons
Oer Commons: Classifying Triangles
In this lesson, students learn to classify triangles by the size of the angles and the measures of the sides. Students will use interactives to explore equilateral, isosceles, scalene, acute, obtuse, and right triangles. Included are...
Math Open Reference
Math Open Reference: Triangles
A complete reference guide to types of triangles and triangle perimeter and area. It provides definitions and interactive animated activities that enhance further explanation.
ClassFlow
Class Flow: Classifying Triangles
[Free Registration/Login Required] This lesson covers methods of classifying triangles, both according to the length of their sides and by the measure of their interior angle.
ClassFlow
Class Flow: Understanding Basic Triangles
[Free Registration/Login Required] This lesson presents an introduction to triangles and the methods of identifying them. It includes opportunities for students to interactively identify triangles. It also includes: assessment questions...