Activity
Math Is Fun

Math Is Fun: Acute Angle

For Students 3rd - 8th Standards
This very basic website gives a clear, simple explanation of what an acute angle is.
Activity
Math Is Fun

Math Is Fun: Reflex Angle

For Students 3rd - 8th Standards
This math tutorial provides an illustrated explanation of a reflex angle.
Unit Plan
E-learning for Kids

E Learning for Kids: Math: World of Fish: Space

For Students 4th - 6th
Join Otto at the Phantasia construction site. Will you help him build a new playground?
Activity
University of Cambridge

University of Cambridge: Nrich: Take the Right Angle

For Students 3rd - 5th Standards
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...
Website
PBS

Pbs Learning Media: Directions to Hen Rock

For Students 3rd - 9th Standards
The CyberSquad has to deal with angles and distances to locate a treasure chest in this video segment from Cyberchase.
Unit Plan
CK-12 Foundation

Ck 12: Elem Math: Classifying Triangles by Identifying the Number of Equal Sides

For Students 3rd - 5th Standards
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on classifying triangles based on the number of equal sides.
Activity
National Council of Teachers of Mathematics

Nctm: Figure This: Nctm Math Challenge Three Squares (Pdf)

For Students 3rd - 8th Standards
If you think you can handle the Pythagorean Theorem, then this is a math challenge you should try. Explore geometric relationships and measurement in this one page activity from the NCTM Math Challenges for Families series.
Activity
National Council of Teachers of Mathematics

Nctm: Figure This: Windshield Wipers

For Students 3rd - 8th
Test your mathematical aptitude with challenge exploring the concepts of measurement and geometry. Find the area of the windshield wipers to figure out who sees better in the rain, car drivers or truck drivers. An activity from the NCTM...
Whiteboard
ClassFlow

Class Flow: Circle Vocabulary

For Teachers 3rd - 8th
[Free Registration/Login Required] This lesson lets students identify, draw, and measure parts of a circle. The lesson compliments 5th grade Harcourt Math, Lesson 23.4. Activote assessment is included at the end of the lesson.