Instructor’s Solutions Manual
Elementary Geometry for
College Students
SIXTH EDITION
Daniel Alexander
Parkland College, Professor Emeritus
Geralyn M. Koeberlein
Mahomet-Seymour High School, Mathematics Department Chair, Retired
Prepared by
Geralyn M. Koeberlein
Mahomet-Seymour High School, Mathematics Department Chair, Retired
Daniel Alexander
Parkland College, Professor Emeritus
Australia • Brazil • Mexico • Singapore • United Kingdom • United States
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1 2 3 4 5 6 7 17 16 15 14 13
, Contents
Suggestions for Course Design iv
Chapter-by-Chapter Commentary v
Solutions
Chapter 1 Line and Angle Relationships 1
Chapter 2 Parallel Lines 22
Chapter 3 Triangles 49
Chapter 4 Quadrilaterals 73
Chapter 5 Similar Triangles 99
Chapter 6 Circles 133
Chapter 7 Locus and Concurrence 156
Chapter 8 Areas of Polygons and Circles 172
Chapter 9 Surfaces and Solids 205
Chapter 10 Analytic Geometry 228
Chapter 11 Introduction to Trigonometry 270
Appendix A Algebra Review 291
iii
© 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as
permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.
, Suggestions for Course Design
The authors believe that this textbook would be appropriate for a 3-hour, 4-hour, or 5-hour
course. Some instructors may choose to include all or part of Appendix A (Algebra Review)
due to their students’ background in algebra. There may also be a desire to include The
Introduction to Logic, found at our website, as a portion of the course requirement. Inclusion
of some laboratory work with a geometry package such as Geometry Sketchpad is an option
for course work.
3-hour course
Include most of Chapters 1–8. Optional sections could include:
Section 2.2 Indirect Proof
Section 2.3 Proving Lines Parallel
Section 2.6 Symmetry and Transformations
Section 3.5 Inequalities in a Triangle
Section 6.4 Some Constructions and Inequalities for the Circle
Section 8.5 More Area Relationships in the Circle
4-hour course
Include most of Chapters 1–8 and include all/part of at least one of
these chapters:
Chapter 9 Surfaces and Solids (Solid Geometry)
Chapter 10 Analytic Geometry (Coordinate Geometry)
Chapter 11 Introduction to Trigonometry
5-hour course
Include most of Chapters 1–11 as well as topics desired from Appendix A and/or
The Introduction to Logic (see website).
Daniel C. Alexander
Geralyn M. Koeberlein
iv
© 2015 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as
permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.