TED-Ed
TED-Ed: Daniel Finkel: Can you solve the unstoppable blob riddle?
A shooting star crashes onto Earth and a hideous blob emerges. It creeps and leaps, it glides and slides. It's also unstoppable: no matter what you throw at it, it just re-grows and continues its rampage. The only way to save the planet...
Curated Video
Determining Similarity of Acute Triangles by Examining Corresponding Parts
In this video, students learn how to determine if two acute triangles are similar by examining their corresponding parts. They review the concept of similarity transformations and how they preserve shape but may change size.
Brian McLogan
How does the pythagorean inequality theorem prove acute triangles
Learn about the Pythagorean theorem. The Pythagoras theorem is a fundamental relation among the three sides of a right triangle. It is used to determine the missing length of a right triangle. The Pythagoras theorem states that the...
NUMBEROCK
Triangles
Skateboards, mountain climbing, billiards' Don't you just love this stuff? That's why NUMBEROCK put it all into this song about triangles that is filled with real-world connections. Triangles are all around us, so it is easy to make this...
Scholastic
Study Jams! Classify Triangles
Jam on with this multi-faceted activity teaching triangle classification. Start with a learner-paced lesson describing the different qualities of triangles and follow with a fun karaoke session. Also provided are two types...
Flipped Math
Triangles
Take time to tackle triangles. Scholars watch a video that first reviews the types of triangles. They then investigate the Isosceles Triangle Theorem and see how to apply it to solve problems. At the end, individuals also learn how to...
TED-Ed
Can You Solve the Unstoppable Blob Riddle?
Viewers of an entertaining short video have an opportunity to save the world! All they have to do is solve the unstoppable blob riddle. Acute learners will have no problem with this problem.
CK-12 Foundation
Applications of the Pythagorean Theorem: Lesson
The Pythagorean Theorem works for something other than right triangles; show your class all it can do. Using information from the Pythagorean Theorem, the video shows how to determine whether a triangle is an acute or obtuse triangle....
CK-12 Foundation
Altitudes: Examples
Find the location of altitudes—from any elevation! The video presents the definition of an altitude of a triangle. By drawing examples, the segment of a larger geometry playlist highlights the location of altitudes of various triangle...
CK-12 Foundation
Classifying Triangles: Lesson
That's correct, it is right and scalene. The video introduces the two methods for classifying triangles, sides, and angles. A resource in the playlist for basic geometry provides the definitions for each of the classifications.
Math Antics
Triangles
What has three sides and is adorable? A-cute triangle. The resource introduces triangles and how to classify them by sides and angles or both. The video concludes with using the sum of the angles of a triangle to show how to solve for a...
Krista King Math
Pythagorean Inequalities
Right, acute, or obtuse: how do you know? Learners observe how to use the Pythagorean Theorem to determine the type of triangle from a set of side lengths. The video includes an example of each triangle type.
Curated OER
What are Acute, Obtuse, and Right Triangles?
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: right, isosceles, equilateral, scalene, obtuse, and acute. Watch this video to learn...
Massachusetts Institute of Technology
Mit: Blossoms: Are Random Triangles Acute or Obtuse?
An MIT mathematics professor examines the probability of a random triangle being either obtuse or acute in a video [32:44] on geometrical probability. Video is accompanied by a teacher's guide, transcript, and several links on linear...
Sophia Learning
Sophia: Classifying Triangles
This video lesson describes and provides examples of right, acute, and obtuse triangles. Students can check their understanding with an assessment. [2:24]
Sophia Learning
Sophia: Classifying Triangles by Angle
This video lesson shows examples of classifying triangles by their angle measurements. Students can check their understanding with an assessment. [3:54]