Grades 8-12 
Mathematics 
Geometry 
Standard 21
Students prove and solve problems regarding relationships
among chords, secants, tangents, inscribed angles and
inscribed and circumscribed polygons of circles.
 
 
Resources
Lesson Plans
Assessments
Geometry 
Larson/Boswell/Stiff, 1995,  
D.C. Heath and Company  

Section References  

10.1 Exploring Circles  

10.2 Porperties of  
Tangents  

10.3 Central Angles 
and Arcs  

10.4 Arcs and Chords  

10.5 Inscribed Angles  

10.6 Other Angle Relationships  

10.7 Extended Application: Equations of Circles 

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.   

Calculator Reference Site   

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

Previously Published Data 

1.) Students will draw and label a circle and all of it parts. 

2.) Students will work in groups to discover a special property of the term (chord, secant, tangent, inscribed angle of a circle, inscribed circle in a polygon, circumscribed circle about a polygon) they were assigned and prepare several problems based on their discovery for the class to solve. Each group will present its discoveries to the class in a presentation method of the members' choice. The class may critique the presentations based on a rubric that addresses involvement of all group members and coverage of the discovery. For example, tangent segments to a circle from an external point are equal. BD = BC 
Previously Published Data 

1.) Students will label all parts of a circle. 

2.) Students will use the relationships to calculate the measures of angles and segments of tangents, chords, secants, inscribed angles, and inscribed and circumscribed polygons.