Teachers' Domain is moving soon to its new and improved home — PBS LearningMedia!          Learn More

# Finding the Circle's Center

Resource for Grades 3-6

Media Type:
Video

Running Time: 3m 40s
Size: 10.1 MB

or

Source: Cyberchase: "Borg of the Ring"

### Collection Developed by:

Collection Credits

### Collection Funded by:

Funding for the VITAL/Ready to Teach collection was secured through the United States Department of Education under the Ready to Teach Program.

In this video segment from Cyberchase, the CyberSquad must reclaim the Totally Rad Ring by making an exact duplicate. To do that, they must determine the radius of the ring and the exact center. The ring then must be placed in the exact center of a circle.

Connections

TERC(2006)
Turtle Paths
Investigation 2, Sessions 1-3: pp. 31-40

Teaching Tips

Here are some Frame, Focus and Follow-up suggestions for using this video in a math lesson.

What is Frame, Focus and Follow-up?

Frame: All shapes have certain features or properties that help us define them. For example, how do we know when a four-sided shape should be called a square and not a trapezoid? Or what is it about a circle that makes it a circle? Sometimes measuring helps with this process of defining a shape. Can you think of an example?

Focus: As you watch this segment try to determine what the CyberSquad knows about circles that enables them to find the exact center of a circle. How does the CyberSquad use this knowledge to physically go about finding the center?

Follow Up: What properties of a circle did the CyberSquad know about that made measuring and finding the exact center of the circle possible? If you had to find the exact center of a pie plate or Frisbee®, how would you do it? What materials would you need? If you had to find the exact center of a square, would you do it differently? Why?

Transcript

INEZ: We need to find the center of the circle, now!

JACKIE: Try this! We can make a pattern of this

INEZ: Cool! The cloth matches the Circle! Make sure the edges match up.

JACKIE: I’ll mark the halfway fold line on the ground.

INEZ: Now unfold and fold the other way! Now make that line! Pull it!

JACKIE: There it is!

INEZ: Where the lines cross!

JACKIE: The center of the circle!

INEZ: All we need now is the ring! Where are those guys?

DIGIT: Hacker's gaining on us!

HACKER: I WANT MY RING BACK!

MATT: LOOK OUT!

HACKER: Ahhhh!!!!

SLIDER: Thanks. Let’s go.

INEZ: Slider!

JACKIE: You made it!

DIGIT: What are we...chopped liver?

SLIDER: Did you find the center of the circle?

INEZ/JACKIE: Yup!

SLIDER: Okay!

MATT: Time out! We better double check to make sure it's the exact center!

SLIDER: Matt's right. If it's not the exact center - the circle won't accept it.

SLIDER: My father knows all about the ring. Once, Hacker tried to get him to find it for him. My father wouldn’t do it - haven't seen him since.

MATT: GEE.

SLIDER: C'mon, double-check. No time to waste!

JACKIE: We can use the yo-yo again! If this point really is the center of the circle, then every point on the edge should be the same distance from the center.

MATT: Got the radius! It's the same distance from the center all the way around! That is the exact center! Put the ring down! Hurry!

HACKER: I don't think so!

INEZ: Nice hair, Hacker.

HACKER: Jealous?

INEZ: Huh!

HACKER: Now give me that ring!

INEZ: Catch!

SLIDER: It's all yours, Hacker.

JACKIE/INEZ/DIGIT: What?!/Slider, no! /Don't do it!!!

MATT: I knew he was bad news!

HACKER: That's more like it! Now, to get rid of you meddling Munchkins! My heart's desire is for you all to be banished to the Northern Frontier! -Forever! What...it didn't work! This isn't the real ring!

SLIDER: That's right - I made two fake rings - just in case. Here's the real one. Matt...!

HACKER: Stop him...!!!

MATT: Touchdown!

HACKER: Yeeeowwwww!!!

MATT: The Totally Rad Ring is safe forever! We did it!

JACKIE/INEZ: We saved Motherboard!

MATT: Hey. Thanks Slider.

INEZ: Gee, do you think we will ever see him again?

JACKIE: I hope so.

DIGIT: I have feeling we will.

Standards

to: