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Thinkwell's Geometry course contains all of the geometry help you need. This complete online Geometry course is fun and easy to use, because of the fun and effective videos. After watching a geometry video lesson, you can review and practice with automatically graded exercises that give you an instant feedback, as well as printable geometry worksheets with answer keys. It covers the same material as the most popular geometry textbooks, so it's a great study aid for learning the concepts that you didn't learn from your teacher. And because it's available for one flat rate, instead of by the hour, it's much better than a geometry tutor.

Our videos feature award-winning teacher Edward Burger, whose multimedia video lessons have been created to work with any learning style. The course includes automatically graded exercises and tests, geometry practice worksheets, a geometry glossary (geometry dictionary) of geometry terms, and our interesting and easy-to-use animated Interactivities.

Our complete Geometry package includes:
  • 12-month Online Subscription to our complete Geometry course with video lessons, automatically graded geometry problems, and much more.
  • CD Set (optional) contains all of the video lessons so that you can watch them when you're away from the internet.

CD Sets require the purchase of an online subscription.

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Geometry Materials

Online Subscription, 12-month access

Access to a complete online package that includes everything you need:

  • High quality video lessons explain all of the Geometry math topics and concepts
  • Automatically graded geometry problems with immediate feedback allow you to track your progress
  • Printable full-color illustrated notes help you review what you've learned in the video lesson
  • Subscriptions start when you are ready. Buy now and activate your course anytime you like. Wait up to one year to activate your subscription; your 12-month subscription doesn't begin until you say so!

CD Set Video Lectures on CD-ROM

This optional CD-ROM set delivers the exact same video lectures delivered online, but without an internet connection. Online Subscription is required; CDs not sold separately. The CDs only contain the videos.

Geometry Details

Thinkwell's Geometry has all the features your home school needs:

  • Aligned to Geometry National Math Standards
  • More than 100 topics with 400+ engaging video lessons (see sample)
  • 1300+ interactive exercises with immediate feedback allow you to track your progress.
    (see sample)
  • 24 animated interactivities with audio
  • Geometry tests, including 13 chapter tests, as well as practice tests, a midterm, and a final exam
  • Printable illustrated notes for each topic
  • Real-world application examples in both lectures and exercises
  • Closed captioning for all video lessons
  • Glossary of more than 250 mathematical terms
  • Review of essential algebra concepts and applications
  • Brand new content to help students advance their mathematical knowledge:
    • measuring and constructing segments and angles
    • using inductive and deductive reasoning
    • mathematical proofs
    • parallel and perpendicular lines
    • triangle congruence: SSS, SAS, ASA, AAS, HL, and CPCTC
    • medians, altitudes, and midsegments in triangles
    • the Pythagorean theorem
    • properties and attributes of polygons and quadrilaterals
    • similarity relationships
    • trigonometric ratios
    • perimeter, circumference, and area of two-dimensional shapes

Table of Contents

(Expand All - Close All)

1. Fundamentals of Geometry

  • 1.1 Points, Lines, Planes, and Angles
    • 1.1.1 Understanding Points, Lines, and Planes
    • 1.1.2 Measuring and Constructing Segments
    • 1.1.3 Measuring and Constructing Angles
    • 1.1.4 Pairs of Angles
  • 1.2 Coordinate and Transformation Tools
    • 1.2.1 Using Formulas in Geometry
    • 1.2.2 Midpoint and Distance in the Coordinate Plane
    • 1.2.3 Transformations in the Coordinate Plane

2. Reasoning and Writing Geometric Proofs

  • 2.1 Inductive and Deductive Reasoning
    • 2.1.1 Using Inductive Reasoning to Make Conjectures
    • 2.1.2 Conditional Statements
    • 2.1.3 Using Deductive Reasoning to Verify Conjectures
    • 2.1.4 Biconditional Statements and Definitions
  • 2.2 Mathematical Proof
    • 2.2.1 Algebraic Proof
    • 2.2.2 Geometric Proof
    • 2.2.3 Flowchart and Paragraph Proofs

3. Parallel and Perpendicular Lines

  • 3.1 Lines with Transversals
    • 3.1.1 Planes, Lines, and Angles
    • 3.1.2 Angles, Parallel Lines, and Transversals
    • 3.1.3 Proving that Lines are Parallel
    • 3.1.4 Properties of Perpendicular Lines
  • 3.2 Slope and the Equation of a Line
    • 3.2.1 Finding the Slope Given Two Points
    • 3.2.2 Slope-Intercept Form
    • 3.2.3 Point-Slope Form
    • 3.2.4 Slopes of Parallel and Perpendicular Lines

4. Triangle Congruence

  • 4.1 Triangles and Congruence
    • 4.1.1 Classifying Triangles
    • 4.1.2 Angle Relationships in Triangles
    • 4.1.3 Congruent Triangles
  • 4.2 Proving Triangle Congruence
    • 4.2.1 Triangle Congruence: SSS and SAS
    • 4.2.2 Triangle Congruence: ASA, AAS, and HL
    • 4.2.3 Triangle Congruence: CPCTC
    • 4.2.4 Introduction to Coordinate Proof
    • 4.2.5 Isosceles and Equilateral Triangles

5. Properties and Attributes of Triangles

  • 5.1 Segments in Triangles
    • 5.1.1 Perpendicular and Angle Bisector Theorems
    • 5.1.2 Medians, Altitudes, and Midsegments in Triangles
  • 5.2 Relationships in Triangles
    • 5.2.1 Indirect Proof and Inequalities in One Triangle
    • 5.2.2 Inequalities in Two Triangles
    • 5.2.3 The Pythagorean Theorem
    • 5.2.4 Applying Special Right Triangles

6. Polygons and Quadrilaterals

  • 6.1 Polygons and Parallelograms
    • 6.1.1 Properties and Attributes of Polygons
    • 6.1.2 Properties of Parallelograms
    • 6.1.3 Conditions for Parallelograms
  • 6.2 Other Special Quadrilaterals
    • 6.2.1 Properties of Special Parallelograms
    • 6.2.2 Conditions for Special Parallelograms
    • 6.2.3 Properties of Kites and Trapezoids

7. Similarity

  • 7.1 Similarity Relationships
    • 7.1.1 Ratio and Proportion
    • 7.1.2 Ratios in Similar Polygons
    • 7.1.3 Triangle Similarity: AA, SSS, and SAS
  • 7.2 Applying Similarity
    • 7.2.1 Applying Properties of Similar Triangles
    • 7.2.2 Using Proportional Relationships
    • 7.2.3 Dilations and Similarity in the Coordinate Plane

8. Right Triangles and Trigonometry

  • 8.1 Trigonometric Ratios
    • 8.1.1 Similarity in Right Triangles
    • 8.1.2 Trigonometric Ratios
    • 8.1.3 Solving Right Triangles
  • 8.2 Applying Trigonometric Ratios
    • 8.2.1 Angles of Elevation and Depression
    • 8.2.2 Law of Sines and Law of Cosines
    • 8.2.3 Vectors

9. Extending Perimeter, Circumference, and Area

  • 9.1 Developing Geometric Formulas
    • 9.1.1 Developing Formulas for Triangles and Quadrilaterals
    • 9.1.2 Developing Formulas for Circles and Regular Polygons
    • 9.1.3 Composite Figures
  • 9.2 Applying Geometric Formulas
    • 9.2.1 Perimeter and Area in the Coordinate Plane
    • 9.2.2 Effects of Changing Dimensions Proportionally
    • 9.2.3 Geometric Probability

10. Spatial Reasoning

  • 10.1 Three-Dimensional Figures
    • 10.1.1 Solid Geometry
    • 10.1.2 Representations of Three-Dimensional Figures
    • 10.1.3 Formulas in Three Dimensions
  • 10.2 Surface Area and Volume
    • 10.2.1 Surface Area of Prisms and Cylinders
    • 10.2.2 Surface Area of Pyramids and Cones
    • 10.2.3 Volume of Prisms and Cylinders
    • 10.2.4 Volume of Pyramids and Cones
    • 10.2.5 Spheres

11. Circles

  • 11.1 Lines and Arcs in Circles
    • 11.1.1 Lines That Intersect Circles
    • 11.1.2 Arcs and Chords
    • 11.1.3 Sector Area and Arc Length
  • 11.2 Angles and Segments in Circles
    • 11.2.1 Inscribed Angles
    • 11.2.2 Angle Relationships in Circles
    • 11.2.3 Segment Relationships in Circles
    • 11.2.4 Circles in the Coordinate Plane

12. Transformational Geometry

  • 12.1 Congruence Transformations
    • 12.1.1 Reflections
    • 12.1.2 Translations
    • 12.1.3 Rotations
    • 12.1.4 Compositions of Transformations
  • 12.2 Patterns
    • 12.2.1 Symmetry
    • 12.2.2 Tessellations
    • 12.2.3 Dilations

13. Appendix: Essential Algebra Review

  • 13.1 Solving Equations and Inequalities
    • 13.1.1 Simplifying Expressions
    • 13.1.2 Writing and Solving Two-Step Equations
    • 13.1.3 Solving Two-Step Inequalities
    • 13.1.4 Writing and Solving Multi-Step Equations
    • 13.1.5 Solving Equations with Variables on Both Sides
    • 13.1.6 Systems of Equations
  • 13.2 Graphing and the Coordinate Plane
    • 13.2.1 The Coordinate Plane
    • 13.2.2 Equations, Tables, and Graphs
    • 13.2.3 Graphing Using Intercepts
  • 13.3 Ratio and Proportion
    • 13.3.1 Rates, Ratios, and Proportions
    • 13.3.2 Applications of Proportions
    • 13.3.3 Finding and Using Percents
  • 13.4 Operations with Polynomials and Factoring
    • 13.4.1 Adding and Subtracting Polynomials
    • 13.4.2 Multiplying and Dividing Monomials
    • 13.4.3 Multiplying Monomials by Polynomials
    • 13.4.4 Multiplying Binomials
    • 13.4.5 Factoring with the GCF
    • 13.4.6 Factoring x2 + bx + c
    • 13.4.7 Factoring ax2 + bx + c
  • 13.5 Radicals and Solving Quadratics
    • 13.5.1 Radical Expressions
    • 13.5.2 Solving Quadratic Equations by Factoring
    • 13.5.3 Solving Quadratic Equations by Using Square Roots

About the Author

Author BUR

Edward Burger
Williams College

Edward Burger, Professor of Mathematics at Williams College, earned his Ph.D. at the University of Texas at Austin, having graduated summa cum laude with distinction in mathematics from Connecticut College.

He has also taught at UT-Austin and the University of Colorado at Boulder, and he served as a fellow at the University of Waterloo in Canada and at Macquarie University in Australia. Prof. Burger has won many awards, including the 2001 Haimo Award for Distinguished Teaching of Mathematics, the 2004 Chauvenet Prize, and the 2006 Lester R. Ford Award, all from the Mathematical Association of America. In 2006, Reader's Digest listed him in the "100 Best of America". After completing his tenure as Gaudino Scholar at Williams, he was named Lissack Professor for Social Responsibility and Personal Ethics.

Prof. Burger is the author of over 50 articles, videos, and books, including the trade book, Coincidences, Chaos, and All That Math Jazz: Making Light of Weighty Ideas and of the textbook The Heart of Mathematics: An Invitation to Effective Thinking. He also speaks frequently to professional and public audiences, referees professional journals, and publishes articles in leading math journals, including The Journal of Number Theory and American Mathematical Monthly. His areas of specialty include number theory, Diophantine approximation, p-adic analysis, the geometry of numbers, and the theory of continued fractions.

Prof. Burger's unique sense of humor and his teaching expertise combine to make him the ideal presenter of Thinkwell's entertaining and informative video lectures.

Geometry Video lessons

Video Lessons

Geometry Interactive Exercises

Interactive Exercises

Geometry Illustrated Notes

Illustrated Notes

Thinkwell gave clear, concise explanations that helped me go into class already knowing the concepts, or ready to ask for clarification of any concepts that I did not fully understand.