Grades 8-12
Mathematics
Geometry
Standard 2

Students write geometric proofs, including
proofs by contradiction.


 
Resources
Lesson Plans
Assessments
Geometry Larson/
Boswell/Stiff, 1995, D. C. Heath and Company

Section References

2.1 
Exploring Patterns

2.2 
The Structure of Geometry

2.3
Segment and Angle 
Relationships

2.4
Conditional Statements

2.5 
Resoning with Properties 
form Algebra

2.6 
Deductive Reasoning

3.1
Exploring Lines and Planes

3.2 
Connections to Algebra

3.3 
Using the Laws of Logic

3.4
Styles of Proofs

3.5
Properties of Parallel Lines

3.6 Proving Lines are Parallel

3.7 Extended Applications: Vectors

Software

Math Blaster Geometry, Davidson & Associates, Inc. 2996
cd mac/windows

Specific Textbook 
Web Sites

http://www.glencoe.com/
sec/math/prealg/mathnet/

http://www.eduplace.com/
links/

http://www.eduplace.com/

http://www.hmco.com/
college/mathematics/
index.html

http://www.mcdougallittell
.com/

http://www.hmco.com/

http://www.SRA-4KIDS.com/

General Math 
Reference Sites

http://www.learner.org/
sami/view-category.php3
?category=math

http://www.score.k12.ca.us/

http://henson.austin.apple
.com/edres/curric.shtml

http://school.discovery.com/
schrockguide/index.html

http://www.EDsOasis.org/

http://www.math.com/

http://www.nea.org/grants/
free.html

http://www.wcom.com/
marcopolo/

http://www.udel.edu/sine/

http://dewey.chs.chico.k12
.ca.us/math.html

Free Stuff

http://www.nea.org/
grants/free.html

State/National Math 
Ed Organizations

http://www.nctm.org/

http://www.cde.ca.gov/

Calif. Dept. of Ed. Standards, Assessment, Ed. Reference.

Calculuator Reference Site

http://www.ti.com/
calc/docs/calchome.html

Previously Published Data

1.) Students will supply the missing steps in proofs. 

2.) Students will write proofs by contradiction. 
3.) Students will write the negation of statements to help in writing proofs by contradiction. 
4.) Students will write their own deductive proofs. 
5.) Students will do crossword puzzles to help see the process of getting to a conclusion in a roundabout way. A short example of a crossword with sum totals is given below.
 
 



 






Students will place one digit (1 to 9, no zeros) in each square so that the sum of the numbers in each group of squares across or down is the number given. The number below a diagonal is the sum of the numbers below it. The number to the right is the sum of the numbers to the right of it. No digit is to be used more than once.

Previously Published Data

1.) Students will fill in missing statements and reasons in proofs. 

2.) Students will write their own deductive proofs. 
3.) Students will write their own proofs by contradiction.