Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Right Angle Trigonometry
Fourteen problems present practice working with right angle trigonometry. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View Solution" button to check...
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.
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.
Math Open Reference
Math Open Reference: Angles
Everything you wanted to know about angles and more, including 1) how to measure angles 2) types of angles 3) angle relationships and 4) angles around a transversal.
CK-12 Foundation
Ck 12: Geometry: Angle Measures in Given Triangles
[Free Registration/Login may be required to access all resource tools.] Find the degree measure of an unknown angle in given triangles.
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.]
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 activity proceeds vertical, adjacent, alternate interior and alternate exterior angles are explored. Plenty of...
CK-12 Foundation
Ck 12: Geometry: Supplementary and Complementary Angle Pairs
[Free Registration/Login may be required to access all resource tools.] Use reasoning to figure out the measures of missing angle measures
University of Cambridge
University of Cambridge: Nrich: Take the Right Angle
Sharpen your logic, time, and angle recognition skills while working on this challenge. The solution is available to double check your results. (Hint: Use the "90 degree" right angle button on the clock to check if something is a right...
BBC
Bbc: Angles
You can pick up some valuable pointers on angles and lines here. When you finish working your way through the pages you can take an on-line "Test Bite," and check your understanding.
Primary Resources
Primary Resources: Angles
A great place to find teacher resources on angles. Includes worksheets PowerPoint presentations and smartboard files.
Mangahigh
Mangahigh: Shape: Right Angle in a Semi Circle Rule
Test your knowledge of the measurement of angles in a triangle.
National Council of Teachers of Mathematics
Nctm: Figure This: What's My Angle?
Do people with big hands have larger angles between their fingers? See if you can find the answer this question when you try this math challenge on estimating and measuring angles. Discover how understanding angles and geometric shapes...
CK-12 Foundation
Ck 12: Geometry: Angle Classification Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students to classify angles based on their measure.
ClassFlow
Class Flow: Right Angles
[Free Registration/Login Required] This flipchart is designed to introduce the student to the concept of the right angle and to give the student practice in identifying right angles as well as measuring angles with a protractor.
AAA Math
Aaa Math: Types of Triangles Based on Angles
Students can practice classifying triangles based on angle measurements through a series of self-check exercises and timed learning games.
Math.com
Math.com: Building Blocks: Classifying Angles
This geometry resource investigates types of angles. Definitions, detailed examples, and practice problems are included.
ABCya
Ab Cya: Bow and Angle
Join the heroes Loxley, Arrowyn, Busido, and Mockingbird in this epic adventure of Bows and Angles! Practice measuring and reading angles while you defend yourself from treacherous shadow ninjas.
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.
Illustrative Mathematics
Illustrative Mathematics: 4.g Are These Right?
The purpose of this task is for students to measure angles and decide whether the triangles are right or not. Aligns with 4.G.A.2.
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.
Government of Alberta
Learn Alberta: Math Interactives: Exploring Trig Ratios
Investigate the cosine, sine, and tangent ratios of trigonometry using this interactive Learn Alberta math resource. Students will use these ratios to determine a right triangle's unknown side or angle. Be sure to follow the link to the...
Maths Challenge
Maths challenge.net: Right Triangle Equal Parts
A geometry proof problem involving a right triangle and finding angles of equal measure.