Triangle geometry | Euclidean plane geometry | Elementary geometry

In Euclidean geometry, the AA postulate states that two triangles are similar if they have two corresponding angles congruent. The AA postulate follows from the fact that the sum of the interior angles of a triangle is always equal to 180°. By knowing two angles, such as 32° and 64° degrees, we know that the next angle is 84°, because 180-(32+64)=84. (This is sometimes referred to as the AAA Postulate—which is true in all respects, but two angles are entirely sufficient.) The postulate can be better understood by working in reverse order. The two triangles on grids A and B are similar, by a 1.5 dilation from A to B. If they are aligned, as in grid C, it is apparent that the angle on the origin is congruent with the other (D). We also know that the pair of sides opposite the origin are parallel. We know this because the pairs of sides around them are similar, stem from the same point, and line up with each other. We can then look at the sides around the parallels as transversals, and therefore the corresponding angles are congruent. Using this reasoning we can tell that similar triangles have congruent angles. (Wikipedia).

Geometry - Ch. 2: Reasoning and Proofs (21 of 46) What is a Postulate?

Visit http://ilectureonline.com for more math and science lectures! In this video I will explain what is a postulate. A postulate, or axium, is a proposition that is not proved or demonstrated but considered to be self evident. It is a “truth” that is accepted. A postulate serves as a sta

From playlist GEOMETRY CH 2 PROOFS & REASONING

Geometry - Ch. 2: Reasoning and Proofs (22 of 46) Postulate 1: Ruler (Numberline)

Visit http://ilectureonline.com for more math and science lectures! In this video I will explain Postulate 1:The Ruler, or Number Line, Postulate – points on a line have corresponding points on a number line such that they can have “x-values” called “coordinates” of the points (x1, x2, x3

From playlist GEOMETRY CH 2 PROOFS & REASONING

Geometry - Ch. 3: Proofs (5 of 17) Postulates Needed for Proofs

Visit http://ilectureonline.com for more math and science lectures! In this video I will define what is a postulate, and review some of the basic postulates needed for geometry proofs: linear pair, ruler, segment addition, protractor, angle addition, line intersecting lines, and plane. T

From playlist GEOMETRY CH 3 PROOFS

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From playlist Geometry

Geometry - Ch. 4: Lines and Angles (2 of 37) Postulates of Parallel and Perpendicular Lines

Visit http://ilectureonline.com for more math and science lectures! In this video I will define and explain postulates of parallel and perpendicular lines. 1) If there is a line and a point not on the line then there is exactly one line through the point PARALLEL to the initial line. 2) I

From playlist GEOMETRY CH 4 LINES AND ANGLES

Geometry - Ch. 2: Reasoning and Proofs (29 of 46) Postulate 8: The Plane Postulate

Visit http://ilectureonline.com for more math and science lectures! In this video I will explain Postulate 8: The Plane Postulate – Through any 3 non-collinear points, exists exactly one plane. Next video in this series can be seen at: https://youtu.be/NuiTMuNaUdA

From playlist GEOMETRY CH 2 PROOFS & REASONING

This video focuses on how to prove two triangles congruent using the Angle-Angle-Side (AAS) Postulate. In particular, the concepts of midpoint, parallel lines and alternate interior angles are explored in this video. I also teach how to use diagrams as a tool for writing an organized proof

From playlist Geometry

Triangle Congruence Theorems, Two Column Proofs, SSS, SAS, ASA, AAS Postulates, Geometry Problems

This geometry video tutorial provides a basic introduction into triangle congruence theorems. It explains how to prove if two triangles are congruent using the SSS, SAS, ASA, and AAS postulate using two column proofs. Here is a list of topics contained in the statements and reasons of th

From playlist Geometry Video Playlist

Writing the contrapositive statement from a conditional statement

👉 Learn how to find the contrapositive of a statement. The contrapositive of a statement is the switching of the hypothesis and the conclusion of a conditional statement and negating both. If the hypothesis of a statement is represented by p and the conclusion is represented by q, then the

From playlist Contrapositive of a Statement

Proving Triangles are Similar AA SAS SSS

I introduce the AA Postulate and the SAS & SSS to show you how to prove two triangles are similar. This video includes about 5 examples. The last word in the definition of SAS for similar triangles should be similar, not congruent. Check out http://www.ProfRobBob.com, there you will fin

From playlist Geometry

This video tutorial provides a basic introduction into geometry. My E-Book: https://amzn.to/3B9c08z Video Playlists: https://www.video-tutor.net Homework Help: https://bit.ly/Find-A-Tutor Subscribe: https://bit.ly/37WGgXl Support & Donations: https://www.patreon.com/MathScienceTuto

From playlist Geometry Video Playlist

Congruent Triangles ASA AAS Triangle Congruence

I introduce the ASA Postulate and the AAS Theorem for proving two triangles are congruent and work through 4 examples of including 2 column proofs. EXAMPLES AT 0:50 7:19 9:45 13:38 Find free review test, useful notes and more at http://www.mathplane.com If you'd like to make a donation to

From playlist Geometry

Triangle Similarity - AA SSS SAS & AAA Postulates, Proving Similar Triangles, Two Column Proofs

This geometry video tutorial provides a basic introduction into triangle similarity. it explains how to use two column proofs in order to prove if two triangles are similar using the mostly the AA postulates. Other triangle similarity postulates mentioned are the AAA, SSS, and SAS postul

From playlist Geometry Video Playlist

Right Angle Theorem - SSS & AAS - Two Column Proofs

This geometry video tutorial provides a basic introduction into the right angle theorem and provides examples of how to use it in a two column proof problem along with cpctc and triangle congruence theorems such as the SSS and AAS postulates. Geometry Playlist: https://www.youtube.com/w

From playlist Geometry Video Playlist

Geometry Proofs - Isosceles Triangles - SAS & AAS

This video tutorial focuses on geometry proofs on isosceles triangles beyond cpctc. The triangle congruence theorems mentioned in this are the SAS & AAS postulates. This video contains 3 example problems on proving isosceles triangles in the form of two column proofs. Geometry Playlist:

From playlist Geometry Video Playlist

Detour Proofs - Double Triangle Congruence

This geometry video tutorial focuses on detour proofs which is basically proving that two triangles are congruent twice. Triangle congruence theorems in this lesson include the SSS, SAS, and AAS postulates. This geometry video contains two examples on two column proofs with cpctc. Geome

From playlist Geometry Video Playlist

Introduction to Congruent Triangles

Complete videos list: http://mathispower4u.yolasite.com/ This video will define congruent triangles and state the ways to prove two triangles are congruent.

From playlist Triangles and Congruence

Finding congruent triangles | Congruence | Geometry | Khan Academy

Using the SSS, ASA, SAS, and AAS postulates to find congruent triangles Practice this lesson yourself on KhanAcademy.org right now: https://www.khanacademy.org/math/geometry/congruent-triangles/cong_triangle/e/congruency_postulates?utm_source=YT&utm_medium=Desc&utm_campaign=Geometry Wat

From playlist High School Geometry | High School Math | Khan Academy

CPCTC Geometry Proofs Made Easy, Triangle Congruence - SSS, SAS, ASA, & AAS, Two Colmn Proofs

This video tutorial provides a basic introduction into CPCTC geometry proofs. CPCTC stands for "corresponding parts of congruent triangles are congruent" It's the step that comes right after proving the congruence of two triangles. Some triangle congruence theorems you need to know are

From playlist Geometry Video Playlist

How to determine the contrapositive of a conditional statement

👉 Learn how to find the contrapositive of a statement. The contrapositive of a statement is the switching of the hypothesis and the conclusion of a conditional statement and negating both. If the hypothesis of a statement is represented by p and the conclusion is represented by q, then the

From playlist Contrapositive of a Statement