ClassFlow
Class Flow: All About Angles
[Free Registration/Login Required] This flipchart gives an introduction to angles, reading a protractor, naming and classifying angles. It also includes opportunities to practice these skills. The lesson is aligned with the 5th grade...
Homeschool Math
Homeschool Math: Triangles
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.
Texas Instruments
Texas Instruments: Classifying a Triangles by Their Angle Measure Using Cabri Jr
This activity uses Cabri Jr to classify triangles according to their angle measure. [Requires Adobe Reader.]
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.
ClassFlow
Class Flow: Angle Measurement
[Free Registration/Login Required] This flipchart uses the protractor tool to understand the classification and naming of angles: acute, obtuse and right.
ClassFlow
Class Flow: Angle Facts
[Free Registration/Login Required] This lesson is a thorough review of all types of angles (e.g. obtuse, right, scalene, isosceles, equilateral, alternate) with wonderful diagrams to reinforce thinking skills.
Ducksters
Ducksters: Kids Math: Angles Glossary and Terms
Math glossary and terms on angles for kids. Learn the definitions used in this mathematics subject such as acute, obtuse, and right angles on this site.
Oswego City School District
Regents Exam Prep Center: Geometry Vocabulary Resources
A list of geometry definitions and a matching activity.
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 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.
Oswego City School District
Regents Exam Prep Center: Area of a Triangle and Parallelogram Using Trig
How can trigonometry be used to find the area of a triangle or parallelogram? Does the triangle need to be a right triangle, and how accurate can the results possibly be? The answers to these questions are found here along with several...
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.
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.
Mr. Martini's Classroom
Mr. Martini's Classroom: Basic Geometry: Points, Lines, and Angles
Students can review basic geometric terms using these self-check, multiple choice questions. Three levels of questions are provided.
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...
Doina Popovici
Math Play: Classifying Triangles
Practice identifying triangles as either acute, right, or obtuse in this interactive game.
Mathigon
Mathigon: Geometry: Triangles and Trigonometry: Properties of Triangles
This lesson focuses on the properties of triangles, a closed shape that has three sides, three vertices, and and three internal angles. There are different types of triangles such as a right triangle, obtuse, and acute based on the...
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.
Sophia Learning
Sophia: Triangle Height: Lesson 2
This lesson will demonstrate how to locate the height in an obtuse, right, and acute triangle. It is 2 of 5 in the series titled "Triangle Height."
Sophia Learning
Sophia: Triangle Height: Lesson 4
This lesson will demonstrate how to locate the height in an obtuse, right, and acute triangle. It is 4 of 5 in the series titled "Triangle Height."
Quia
Quia: Irregular Plurals
Produced by Quia, to allow the user to take an eleven question quiz reviewing different types of angles.
Khan Academy
Khan Academy: Area of Triangles
Practice finding the area of right, acute, and obtuse triangles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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...
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.