RWM103: Triangle Inequality Theorem | Saylor Academy

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Read this article and watch the videos. Focus on the examples of solving for unknown length and making conclusions about lengths of legs. Pay attention to how to determine whether a given set of lengths will form a triangle.

Click on Triangle Inequality Theorem to open the resource.

COURSE INTRODUCTION

Course Syllabus

Unit 1: The Basics of Geometry

1.1: Language and Notation

The Language and Notation of Basic Geometry

Lines, Line Segments, and Rays

1.2: The Distance between Two Points

The Distance between Two Points

1.3: Midpoints and Segment Bisectors

Midpoints and Segment Bisectors

1.4: Measuring Angles

Angles

Measuring Angles

1.5: Congruent Angles and Angle Bisectors

Congruent Angles and Angle Bisectors

1.6: Acute, Obtuse, and Right Angles

Acute, Right, and Obtuse Angles

1.7: Complementary and Supplementary Angles

Complementary and Supplementary Angles

Practice with Complementary and Supplementary Angles

1.8: Linear Pairs

Linear Pairs

1.9: Vertical Angles

Vertical Angles

Equations with Vertical Angles

Practice Solving Problems with Vertical Angles

1.10: Polygon Classification

Classifying Polygons

Unit 2: Parallel and Perpendicular Lines

2.1: Parallel, Perpendicular, and Skew Lines

Identifying Parallel and Perpendicular Lines

2.2: Angles and Transversals

Angles, Parallel Lines, and Transversals

2.3: Corresponding Angles

Corresponding Angles

2.4: Alternate Interior Angles

Alternate Interior Angles

2.5: Alternate Exterior Angles

Alternate Exterior Angles

2.6: Same Side Interior Angles

Same Side Interior Angles

2.7: Distance Formula in the Coordinate Plane

Using the Distance Formula

Practice Using the Distance Formula

Unit 3: Triangles, Congruence, and Other Relationships

3.1: Triangle Classification

Triangle Classification

3.2: Triangle Sum Theorem

Using the Triangle Sum Theorem

Practice Using the Exterior Angle Theorem

3.3: Exterior Angle Theorem

Using the Exterior Angle Theorem

Practice Using the Exterior Angle Theorem

3.4: Congruent Figures

Congruent Figures

3.5: Congruent Triangles and SSS

Congruent Triangles and the SSS Postulate

3.6: Other Triangle Congruence Postulates

The SAS, ASA, and AAS Postulates

3.7: Calculating Congruent Triangles

Congruent Triangles

Practice with Congruent Triangles

Practice with Angles in Congruent Triangles

3.8: Isosceles Triangles

Isosceles Triangles

3.9: Equilateral Triangles

Equilateral Triangles

Unit 4: Triangle Relationships

4.1: Midsegment Theorem

Midsegment Theorem

4.2: Perpendicular Bisectors

Perpendicular Bisectors

4.3: Angle Bisectors

Angle Bisectors

4.4: Medians

Triangle Medians and Centroids

Using Medians and Centroids to Solve Unknown Quantities

4.5: Altitudes

Altitudes

4.6: Triangle Inequality Theorem