Khan Academy
Khan Academy: Draw Right, Acute, and Obtuse Angles
Create an acute, right, or obtuse angle using a given vertex.
CK-12 Foundation
Ck 12: Elem Math: Classifying Angles as Right, Acute, or Obtuse
[Free Registration/Login may be required to access all resource tools.] In this learning module, students are presented with angles and must identify what type each is. An accompanying video demonstrates a sample problem. [2:10] A set of...
CK-12 Foundation
Ck 12: Elem Math: Counting Right Angles in a Diagram
[Free Registration/Login may be required to access all resource tools.] Practice counting the number of right angles in a diagram in this learning module. Includes video demonstration of a sample problem [2:11] and practice questions.
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...
Texas Instruments
Texas Instruments: Classifying Angles
Students will create a variety of angles using the Geoboard APP. The teacher will use Screen Capture to display the angles created by the students and will lead a discussion on whether the angles are acute, right, or obtuse.
Math Is Fun
Math Is Fun: Angles
Definitions of different types of angles along with images and an interactive tool through which you can create acute, right, straight, obtuse, and reflex angles. View the parts of an angle, and learn the proper way to label angles.
Better Lesson
Better Lesson: Finding Angles
The three types of angles, right, acute, and obtuse, exist in our everyday surroundings. Students find these angles using classroom items.
ClassFlow
Class Flow: Angle Tester
[Free Registration/Login Required] This flipchart reviews right, acute and obtuse angles with students. An Activote review is included at the end.
ClassFlow
Class Flow: Angles Votes
[Free Registration/Login Required] Using this flipchart, students will be able to identify various angles based on mathematical criteria. Questions are related to right, acute, and obtuse angles.
Alabama Learning Exchange
Alex: Angle Scavenger Hunt
In this lesson, students will explore straight, right, acute, and obtuse angles. Students will go on a scavenger hunt throughout the school to search for examples of these types of angles. The students will use digital cameras to record...
Analyze Math
Analyze Math: Angles in Geometry
Definitions and properties of angles in geometry are explored. Topics discussed are right, acute, and complementary angles. Practice exercises with solutions are included.
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...
Shodor Education Foundation
Shodor Interactivate: Lesson: Angles
This upper elementary and middle school lesson plan introduces the concept of acute, obtuse and right angles. Also, as the lesson plan proceeds vertical, adjacent, alternate interior and alternate exterior angles are explored. Plenty of...
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.
CK-12 Foundation
Ck 12: Elem Math: Classifying Right Obtuse or Acute by Angle Measure
[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems on how to classify triangles based on angle measures.
CK-12 Foundation
Ck 12: Volume of Pyramids: Right Angles in a Game of Pool
[Free Registration/Login Required] Students explore classifying angles by navigating through the interactive learning module and then answering questions that go along with the module. Students can also learn more about the concept by...
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.
Khan Academy
Khan Academy: Angle Types
Determine if an angle is acute, right, or obtuse. A protractor is provided. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Shodor Education Foundation
Shodor Interactivate: Lesson: Angles (Elementary)
For this lesson students will learn what determines whether an angle is acute, obtuse or a right angle.
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.
Khan Academy
Khan Academy: Recognize Angles
Determine if angles in shapes and pictures are acute, right, or obtuse. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
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.
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.