Instructional Video
Khan Academy

Khan Academy: Triangles: Fill in the Blank Triangle Proofs Example 1

9th - 10th Standards
In this video, we listen to how a geometry exercise is completed as the presenter demonstrates the reasoning behind proving that the corresponding parts of triangles are congruent. [9:42]
Instructional Video
Khan Academy

Khan Academy: Triangles: Fill in the Blank Triangle Proofs Example 2

9th - 10th Standards
This video will fill in the blanks in a proof showing that the triangles are congruent.
Instructional Video
Sophia Learning

Sophia: Congruent Triangles: Lesson 3

9th - 10th Standards
This lesson will define the term congruent as it relates to triangles. It is 3 of 11 in the series titled "Congruent Triangles."
Instructional Video
Khan Academy

Khan Academy: Triangles: More on Why Ssa Is Not a Postulate

9th - 10th Standards
Explains why SSA is not a valid postulate for proving triangle congruence.
Instructional Video
Khan Academy

Khan Academy: Sss to Show a Radius Is Perpendicular to a Chord That It Bisects

9th - 10th Standards
More on the difference between a theorem and axiom. Proving a cool result using SSS.
Instructional Video
Sophia Learning

Sophia: Congruent Triangles

9th - 10th
Congruent triangles are explored in this video lesson. [1:54] The tutorial includes detailed examples and a short assessment.
Instructional Video
Sophia Learning

Sophia: Congruent Triangles

9th - 10th
Take a look at two triangles and determine if the triangles are congruent in this video tutorial. [5:13] Check understanding with a quiz.
Instructional Video
Sophia Learning

Sophia: Cpctc (Corresponding Parts of Congruent Triangles)

9th - 10th Standards
Complete a multiple step proof to determine if two triangles are congruent. Take quiz to check for understanding.
Instructional Video
Sophia Learning

Sophia: Determining the Congruence of Triangles

9th - 10th Standards
This video tutorial describes four ways to determine if two triangles are congruent. Students can check their understanding with an assessment. [5:40]
Instructional Video
Sophia Learning

Sophia: Determining the Congruence of Triangles

9th - 10th Standards
Congruent triangles are investigated in this video lesson. The tutorial demonstrates how to use four tricks to determine if triangles are congruent. Students can check their understanding with an assessment. [5:27]
Instructional Video
Sophia Learning

Sophia: Notation for Congruent Parts

9th - 10th Standards
Explore the notation used to represent congruent sides and angles in a triangle. Take a quiz to assess learning.
Instructional Video
Sophia Learning

Sophia: Triangle Congruence Theorem (Hl)

9th - 10th
This video lesson introduces and provides examples of the Hypotenuse-Leg Triangle Congruence Theorem. Students can check their understanding with an assessment.
Instructional Video
Virtual Nerd

Virtual Nerd: Find Missing Angles in an Isosceles Triangle Using Right Triangles

9th - 10th Standards
Discover how identifying your triangle first can be very helpful in solving for a missing interior angle measurement. [3:40]
Instructional Video
Virtual Nerd

Virtual Nerd: How Do You Identify Corresponding Parts in Congruent Triangles?

9th - 10th Standards
Follow along with this tutorial to understand how to identify corresponding sides and angles. [7:31]
Instructional Video
Khan Academy

Khan Academy: Triangles: Finding Congruent Triangles

9th - 10th Standards
This video uses the SSS, ASA, SAS, and AAS postulates to find congruent triangles.
Instructional Video
Khan Academy

Khan Academy: Worked Examples

9th - 10th
Students watch a video about similar and congruent triangles.
Instructional Video
Khan Academy

Khan Academy: Triangles: Congruent Triangle Proof Example

9th - 10th Standards
Students learn how to prove that two triangles are congruent using midpoint of line segments.
Instructional Video
Khan Academy

Khan Academy: Triangles: Congruent Triangle Example 2

9th - 10th Standards
Students watch a video tutorial showing that segments have the same length using triangle congruence properties.
Instructional Video
Khan Academy

Khan Academy: Triangles: Congruent Triangles and Sss

9th - 10th Standards
This video tutorial explains how to use triangle congruence to identify measures of corresponding sides and angles in triangles. Defines side-side-side (SSS) postulate.
Instructional Video
Khan Academy

Khan Academy: Basic Triangle Proofs Module Example 2

9th - 10th Standards
A video proving that the given triangles are congruent by ASA.
Instructional Video
Loyola University Chicago

Math Flix: Isosceles Right Triangle

4th - 6th Standards
This QuickTime movie provides an opportunity to learn about the characteristics of the isosceles right triangles. As you watch and listen to the teacher and student interact it helps clarify the thinking behind applying this concept.
Instructional Video
Study Pug

Study Pug: Enlargements and Reductions With Scale Factors

9th - 10th
When you are asked to make an object bigger or smaller, you will ask, "by how much?". In this case, scale factor can help answer the question. In this lesson, we will practice how to enlarge and reduce objects according to the scale...
Instructional Video
Khan Academy

Khan Academy: Using Similar & Congruent Triangles

9th - 10th Standards
Sal uses the similarity of triangles and the congruence of others in this multi-step problem to find the area of a polygon.
Instructional Video
Sophia Learning

Sophia: Double Diagonals of a Parallelogram: Lesson 4

6th - 8th
This lesson cover the concept that that when both diagonals are drawn in on a parallelogram, two pairs of congruent triangles are formed. It is 4 of 5 in the series titled "Double Diagonals of a Parallelogram."