## Saturday, April 09, 2011

### Coi-cles

Is anyone else panicking that there are less class days left than what you comfortably need to do a good job on all you have left (or want) to teach? Sometimes I'm going along, and then if I get up the nerve, I look at how many non-interrupted-by-other-things classes we have left and compare that to content time needed. SCARY.

Anyway, we started circles just the other day. In true girly fashion, I had them make a foldable that gives the notes in question form on the outside flap and answers (chord, tangent, minor arc, etc) on the inside of the flap.

Some Always, Sometimes, Never, True, False questions that came up:
1. All chords are congruent. (TF?)
2. A chord can contain a diameter. (ASN?)
3. A chord can contain a radius. (ASN?)
4. Concentric circles are similar. (ASN?)
5. If 2 segments are tangent to a circle, then they are congruent (TF?)

And, I made up a new quiz. (Obviously, you can just enter a fake name. I have this so that elsewhere I can know which of my students have taken the quiz.):

1. Anonymous12:06 AM

I like your quiz. Your explanation on the following problem is wrong though. Congruent tangent segments could come from the same endpoint, but they wouldn't have to.

6.

Always, Sometimes, Never:

Two tangent segments to a circle are congruent.
A. Always
C. Never

Explanation
To be congruent, they have to come from the SAME external point.

2. Anonymous12:11 AM

Also, I think the answer to this one is sqrt(73)-3 because 8^2=x(x+6)?

8.

Assume the segment that looks tangent is tangent. Find CB.

A. 2
B. 10
C. 4

3. Anonymous12:14 AM

Oh, of course that last one was wrong. Sorry for working your problems while tired. :)

Nice quiz!

4. Thank you for that "tangent congruent" comment. You are absolutely right, and I fixed the explanation.

5. Anonymous12:12 PM

I'm confused by the ASN questions. "All chords are congruent" - shouldn't that be true false? I guess I'm thinking that Two chords are congruent can be "sometimes" because it is a particular statement, but the universals are messing me up.

Jonathan

6. jd2718: you are absolutely right! Fixed, and thanks :).

7. I am so thankful for the technology and other ideas that you expose me to. I can't wait to create an online quiz for my students. They are going to love it.

8. Keith, You're welcome. I am having fun with the quizzes :).

9. Ms. Cookie Question for you: I am doing the circles chapter right now and I am having a hard time finding how you make the arc symbol over the name of the arc in WORD. I have the equation editor but I can only get it to go over 1 of the letters. Have you done this? DO you know what I am talking about? I hate having to print it out and put it in by hand.

Thanks,
ER

10. I definitely know what you're talking about. I use the "arc" drawing tool. Sometimes it goes all funky on me, but then I just rotate it. After you make one, you can extend or shorten it to be a nice looking arc. THEN you can shrink its size either by using the "boxes" at the corners, or formatting the picture to a smaller size.

Let me know if this helps. If not, then just send me e-mail:
math_mambo@yahoo.com and I can attach a file with an arc on it, and you can just copy and paste it.