CK-12 Foundation
ASA and AAS Triangle Congruence Lesson
The location of the side makes a difference. One of the videos in a geometry playlist introduces angle-side-angle and angle-angle-side congruence relationships. Using drawings, the video shows how these two congruence statements are...
CK-12 Foundation
SSS Triangle Congruence: Lesson
Gimme three sides, mister! The video introduces the Side-Side-Side Triangle Congruence Theorem. Using segments of different lengths, the portion of a larger playlist on geometry shows that only one triangle can be built.
CK-12 Foundation
SAS Triangle Congruence: Lesson
SAS is not just a spy organization. A section of an extensive geometry playlist introduces a way to show two triangles are congruent, SAS. Using diagrams, the video provides an explanation by showing only one triangle is formed with two...
CK-12 Foundation
Creating Congruence Statements: Lesson
Provide a large amount of information in a short statement. A segment of a playlist on basic geometry introduces the notation to denote congruence between two figures. The video shows how to read corresponding parts from a congruence...
CK-12 Foundation
Congruent Triangles: Lesson
Given two congruent triangles, the resource provides the definition of congruent triangles and marks the corresponding parts. The portion of a basic geometry playlist shows the triangles are congruent by moving one on top of the other...
Curated OER
How Do You Identify Corresponding Parts in Congruent Triangles?
Congruent, corresponding, congruent corresponding. If two figures are congruent, then their corresponding sides and corresponding angles are congruent. Is this to be believed? Watch this video and see if the proof is in the pudding.
Sophia Learning
Sophia: Equilateral Triangle Interior Angles Practice Problems: Lesson 1
This lesson will provide practice problems that involve solving for unknown angle and side measures of equilateral triangles. It is 1 of 5 in the series titled "Equilateral Triangle Interior Angles Practice Problems."
Khan Academy
Khan Academy: Geometry: Congruent and Similar Triangles
Explains how to determine if triangles are congruent or similar. [3:53]
Khan Academy
Khan Academy: Geometry: More on Why Ssa Is Not a Postulate
Explains why SSA is not a valid postulate for proving triangle congruence. Practice problems available. This video [7:24] also appears in the Geometry: Triangles strand.
Khan Academy
Khan Academy: Geometry: Two Column Proof Showing Segments Are Perpendicular
In this video tutorial [11:06], the instructor shows how to construct a two-column proof using triangle congruence postulates to prove that two line segments are perpendicular.
Khan Academy
Khan Academy: Geometry:sss to Show a Radius Is Perpendicular to Chord It Bisects
Explains how to prove that a radius is perpendicular to a chord that it bisects by using the side-side-side triangle congruence postulate. [8:19]
Khan Academy
Khan Academy: Geometry: Ca Geometry: Proof by Contradiction
Demonstrates solutions to problems #4-6 of California Geometry released state test questions. Problems address understanding of proof by contradiction and proving triangles congruent. [11:56]
Khan Academy
Khan Academy: Geometry: Figuring Out All Angles for Congruent Triangles Example
Explains how to use given triangle congruency statements to determine the unknown measures of all angles in a diagram where one large triangle is divided into three congruent triangles. [4:35]
Khan Academy
Khan Academy: Geometry: Finding Congruent Triangles
In this video tutorial [7:28], the instructor shows how to determine if two triangles are congruent using different triangle congruence postulates: SSS, SAS, ASA, AAS. Practice problems available.
Khan Academy
Khan Academy: Geometry: Ca Geometry: More on Congruent and Similar Triangles
Demonstrates solutions to problems #17-20 of California Geometry released state test questions. Problems address understanding of similar triangles, parallelograms and properties of the diagonals of parallelograms. [11:11]
Khan Academy
Khan Academy: Geometry: Congruent Triangle Proof Example
Demonstrates how to use triangle congruency to prove that a given point is the midpoint of a given line segment. The proof is written in the form of a two-column proof. Practice problems available. [5:46]
Khan Academy
Khan Academy: Geometry: Congruent Parts of Iscosceles Triangles
Proof that if the legs of an isosceles triangle are congruent then the base angles are congruent and vice versa using triangle congruency postulates. The proof is written as a two-column proof. [9:03]
Khan Academy
Khan Academy: Geometry: Other Triangle Congruence Postulates
In this video tutorial [13:28], the instructor identifies the different triangle congruency postulates: SSS, SAS, ASA, AAS. Practice problems available.
Khan Academy
Khan Academy: Geometry: Congruent Triangles and Sss
In this video tutorial [11:29], the instructor explains how to use triangle congruence to identify measures of corresponding sides and angles in triangles. Defines side-side-side (SSS) postulate. Practice problems available.
Khan Academy
Khan Academy: Geometry: Congruent Triangle Example 2
Demonstrates how to use triangle congruency to prove that corresponding sides of congruent triangles are congruent and then identifies other congruent parts in the overlapping triangle diagram. The proof is written in the form of a...
Sophia Learning
Sophia: Cpctc: Lesson 1
This lesson [8:19] will demonstrate the use of CPCTC in triangle congruency proofs. It is 1 of 4 in the series titled "CPCTC."
Sophia Learning
Sophia: Triangle Angle Combinations: Lesson 5
This lesson explains how you can have 3 acute angles, 1 obtuse and 2 acute angles or 1 right and 2 acute angles in a triangle. It is 5 of 7 in the series titled "Triangle Angle Combinations."
Sophia Learning
Sophia: Triangle Congruence Theorem (Hl): Lesson 3
This lesson will present the Hypotenuse-Leg Triangle Congruence Theorem. It is 3 of 5 in the series titled "Triangle Congruence Theorem (HL)." [4:06]
Sophia Learning
Sophia: Triangle Congruence Theorem (Hl): Lesson 1
This lesson will present the Hypotenuse-Leg Triangle Congruence Theorem. It is 1 of 5 in the series titled "Triangle Congruence Theorem (HL)." [5:01]