Government of Alberta
Learn alberta.ca: Mathematics Glossary: Acute Angle
Get a visual and animated definition of what an acute angle is, as well as examples of acute angles in the real world.
Windstream
Ojk's Precalculus Study Page: Measurement of Angles
An introduction to radian measurement, including converting between radians and degrees. Includes several examples and lots of pictures.
Lawrence Hall of Science
The Math Page: Trigonometry: Measurement of Angles
Here is a site that clearly and thoroughly explains many topics regarding measurement of angles, including standard position, degree measure, and coterminal angles. There are example problems solved, problems for the student to attempt,...
University of Cambridge
University of Cambridge: Nrich: Games Estimating Angles
Use this game to improve your ability to create an angle with a specific number of degrees. You can set the angles to the size you want on this game. Just follow the instructions below it!
University of Cambridge
University of Cambridge: Nrich: Angle A
Sharpen your logic and angle recognition skills by working on this interactive challenge. Solution available.
University of Regina (Canada)
University of Regina: Math Central: Interior Angle Measure of a Polygon
This is a question response page from the University of Regina where you will find an algorithm for finding the number of degrees of any convex polygon.
University of Regina (Canada)
University of Regina: Math Central: Interior Angle Measure of a Polygon
This is a question response page from the University of Regina where one may find an algorithm for finding the number of degrees of any convex polygon.
Mathigon
Mathigon: Geometry: Circle and Pi: Degrees and Radians
Rather than dividing a circle into some number of segments (like 360 degrees), mathematicians often prefer to measure angles using the circumference of a unit circle - a circle with radius 1. This way of measuring angles is called...
CK-12 Foundation
Ck 12: Geometry: Arcs and Angles Study Guide
This study guide on arcs and angles covers key vocabulary, arc measurement in degrees and radians, congruent arcs, bisecting arcs, and the angles on, inside, and outside a circle. Also covers formulas and theorems. It is available for...
Lawrence Hall of Science
The Math Page: Trigonometry: Radian Measure
Here is a site that clearly and thoroughly explains the radian measure of angles. There are example problems solved, problems for the student to attempt, and answers to the student problems.
Khan Academy
Khan Academy: Radians & Degrees
Convert angle measures given in degrees to radians and vice versa.
Purple Math
Purplemath: Converting Between Radians and Degrees
Describes degrees and radians with respect to angles, the reason for the invention and use of radians, and how to convert between radians and degrees.
PBS
Pbs Learning Media: What's a 360?
In this Cyberchase video segment, Harry tries to snowboard and learns how to measure and identify many common angles.
Math Is Fun
Math Is Fun: Acute Angle
This very basic website gives a clear, simple explanation of what an acute angle is.
Texas Instruments
Texas Instruments: Extension: Parallel Lines and the Sum of the Angles
Students construct a line parallel to the base of a triangle and measure the angles formed. They use the construction to prove that the sum of the measures of the interior angles of a triangle is 180 degrees.
Texas Instruments
Texas Instruments: Angles in a Polygon
Students will expore the interior and exterior angle of 3 polygons and develop the formula to calculate the sum of degrees without the measurement of the angles being taken.
E-learning for Kids
E Learning for Kids: Math: Riksjas, Toek Toek: Angles
Students will play interactive games to identify types of angles and measure the angles.
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.
Google
Google for Education: Degrees and Radians
Students label key points on the unit circle in both radians and degrees. They count their way around the circle in 30-degree increments, and then again in increments of radians. Finally, students go through a similar process for angles...
Math Is Fun
Math Is Fun: Reflex Angle
This math tutorial provides an illustrated explanation of a reflex angle.
Quia
Quia: Introduction to Angles
Use this website to practice angle definitions using a matching game format.
Quia
Quia: Introduction to Angles Flashcards
Use this website to practice angle definitions using a flash card format.
Quia
Quia: Introduction to Angles Concentration
Use this website to practice angle definitions using a concentration game format.