3.9 Circles
About Circles
I.SectionObjectives
- Distinguish between radius, diameter, chord, tangent, and secant of a circle.
- Find relationships between congruent and similar circles.
- Examine inscribed and circumscribed polygons.
- Write the equation of a circle.
II.Cross-curricular-Nature
- Look at the following examples of circles in nature.
- These images are Figure 09.01.01
- http://www.naturesmightypictures.blogspot.com/2006/06/circles-in-nature.html
- While these don’t specifically name all of the parts of a circle, use these images to discover the different parts
of a circle. - Where is the radius or the diameter?
- Is there a polygon inscribed in any of the circles?
- For example, look at the sunflower or the rose.
- Are any of the circles similar?
- For example, look at the patterns in the different images. Do you see any similar circles?
- Have a discussion with the students that broadens their thinking about circles and the parts of a circle.
- Then ask the students to find an example of circles in nature.
- Bring it into class the next day.
III.TechnologyIntegration
- Students are going to be working to make connections between circles and real world activities.
- How are circles used in different careers?
- This first example is a designer who makes wheels.
- This designer makes wheels that are used in performance racing.
- As students watch this video, have them make notes on the different geometric elements that are mentioned in
the video. - Then following the video, conduct a discussion on how geometry and wheel design are related.
- http://www.thefutureschannel.com/hands-on_math/spoke_math.php
IV.NotesonAssessment
- Assessment is completed through class discussion.
- Work to have all students participate in the discussion.
- Ask questions of the students and provide feedback as needed.
3.9. Circles