Instructional Video1:29
Curated OER

Obtuse Angles

4th - 6th
A very quick video to define an obtuse angle and to give a few examples.
Instructional Video7:15
Curated OER

How Do You Classify Triangles?

5th - 10th
Triangles are classified by their angle measurement as well as by the length of their sides. Here are some names that identify the types of triangles: isosceles, equilateral, scalene, obtuse, and acute. Watch this video to learn about...
Instructional Video4:15
Curated OER

What are Acute, Obtuse, Right, and Straight Angles?

5th - 8th
Angles are identified by the measurement of their angles. Well, that would make sense. The instructor illustrates four different angles and their names by identifying their degrees. Zero to less than 90 degrees is an acute angle, while...
Instructional Video4:42
Curated OER

How Do You Find Missing Angles in a Transversal Diagram?

6th - 10th
Parallel lines with a transversal and one given value, find the value of the other seven angles. There are many geometric terms about angles and lines to know the meaning of and understand their relationship to each other. Understanding...
Instructional Video6:22
Curated OER

What is a Transversal?

6th - 11th
There are two parallel lines intersected by one straight line, what's that one line called? A transversal. There are a few more things to know about transversal lines and the angles they create. What are vertical angles? Are they...
Instructional Video
Sophia Learning

Sophia: Classifying Triangles by Angle

9th - 10th Standards
This video lesson shows examples of classifying triangles by their angle measurements. Students can check their understanding with an assessment. [3:54]
Instructional Video
Art of Problem Solving

Art of Problem Solving: Introduction to Angles

9th - 10th Standards
Video tutorial uses examples to provide an introduction to angles including right, acute, and obtuse angles. [8:22]