# Ch 5: High School Geometry: Triangles, Theorems and Proofs

Use the following video lessons with quizzes to learn and practice theorems and proofs for triangles. These easy-to-follow lessons are just a portion of our online study guide and video collection.

## High School Geometry: Triangles Theorems and Proofs - Chapter Summary and Learning Objectives

Congruency merely means having the same measure. In this chapter, you can learn triangle congruence postulates and proofs, in addition to finding out how to prove relationships in figures using both similarity and congruence. Explore essential theorems related to triangles through several lessons in this chapter. Upon completion, you should feel comfortable working with:

• Similarity transformations
• Congruency of right triangles and isosceles triangles
• Congruence proofs
• Triangle congruence postulates

Video Objective
Applications of Similar Triangles Learn how to solve applications of similar triangles.
Triangle Congruence Postulates Describe the SAS, ASA and SSS postulates, providing examples of each.
Congruence Proofs Define and use CPCTC to solve an applied problem.
Converse of a Statement Identify the converse of a statement and explain how it must be proven to be true before it may be used as a reason in any proof.
Similarity Transformations When given two figures, use the definition of similarity in terms of similarity transformations to decide if they are similar.
Proving Relationships in Figures Using Congruence and Similarity Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures.
Practice Proving Relationships Use congruence and similarity criteria for triangles to solve problems and to prove relationships in geometric figures.
The AAS Theorem Prove the angle-angle-side theorem.
The HA Theorem Prove the hypotenuse-angle theorem.
The HL Theorem Prove the hypotenuse-leg theorem.
Segment Bisector Theorem Prove the segment bisector theorem by showing an example giving the perpendicular bisector of a given line segment.
Angle Bisector Theorem Prove the angle bisector theorem by showing an example giving the bisector of a given angle.
Congruency of Right Triangles Define the LA and LL theorems.
Congruency of Isosceles Triangles Show how the base angles of an isosceles triangle are congruent.

14 Lessons in Chapter 5: High School Geometry: Triangles, Theorems and Proofs
Test your knowledge with a 30-question chapter practice test
Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
Not Taken
Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
Not Taken

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