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.
CK-12 Foundation
Ck 12: Trigonometry: Pythagorean Theorem to Classify Triangles
[Free Registration/Login may be required to access all resource tools.] Use the Pythagorean Theorem to determine if triangles are acute, obtuse, or right triangles.
Khan Academy
Khan Academy: Identify Triangles by Angles
Practice identifying triangles by their angles as acute, right, or obtuse. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
ClassFlow
Class Flow: Angle This Way
[Free Registration/Login Required] Students will identify right, acute and obtuse triangles using many interactive tools available in ACTIVstudio 3.0. Students will be engaged using a magnifier tool, the fill tool, and drag and drop and...
Doina Popovici
Math Play: Classifying Triangles
Practice identifying triangles as either acute, right, or obtuse in this interactive game.
Illustrative Mathematics
Illustrative Mathematics: G Co Classifying Triangles
The goal of this task is to help students synthesize their knowledge of triangles where only two of the vertices have been given. They will need to know that a triangle inscribed in a circle, with a diameter of the circle as one side, is...
Oswego City School District
Regents Exam Prep Center: Geometry Vocabulary Resources
A list of geometry definitions and a matching activity.
University of Georgia
University of Georgia: Inter Math: Oblique
This site describes the concept of oblique, expressing both triangles and three dimensional solids. Be sure to use the links to related terms, everyday examples, challenging problems, more information, and the interactive check point...
CK-12 Foundation
Ck 12: Converse of the Pythagorean Theorem
[Free Registration/Login may be required to access all resource tools.] Learn about the converse of the Pythagorean Theorem and some of its applications. Also explains how to identify acute and obutse triangles through the use of the...
Texas Instruments
Texas Instruments: Try Angle?
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...
The Math League
The Math League: Figures and Polygons
This site provides definitions of different types of polygons and figures.
University of Saskatchewan (Canada)
University of Saskatchewan: Trigonometric Functions
This site examines the six trigonometric functions from a right triangle point of view. Provides information, examples, and lots of exercises for understanding.
Windstream
Ojk's Precalculus Study Page: The Law of Cosines
An introduction to solving acute and obtuse triangles by using the law of cosines, including a derivation of the formula. Includes several pistures and examples.
Beacon Learning Center
Beacon Learning Center: Anglemania!
Students explore four types of angles in this interactive web lesson.
Wolfram Research
Wolfram Math World: Cut the Knot! Angles
Very good site with links to reviews of various angles.
Windstream
Ojk's Precalculus Study Page: The Law of Sines
An introduction to solving acute and obtuse triangles by using the law of sines, including a derivation of the formula. Includes several pictures and examples.
The Math League
The Math League: Figures and Polygons
This website has basic definitions for most polygons, regular and irregular.
Quia
Quia: Geometric Terms Word Search
Do you need practice remembering or learning different geometry vocabulary words and definitions? This word search is the web site for you! There is a link to a list of terms with definitions you can click if you want to see if you are...
Louisiana Department of Education
Louisiana Doe: Louisiana Believes: Eureka Math Parent Guide: Angle Measure and Plane Figures
A guide to support parents as they work with their students in angle measure and plane figures.