Monthly Schedule

(Geometry, Periods E and F)

W 9/9/09

First day of class. Discussion of Mr. Hansen’s three rules, fire drill quizzes, required equipment, what mathematics is, etc.

 

Th 9/10/09

HW due: Visit www.StudyOfPatterns.com/videos and watch topics 3A and 4; send me a signed e-mail.

 

F 9/11/09

HW due: Read §1.1 (reading notes are required, as shown in the HW guidelines); write §1.1 #5-13 all. A re-quiz on the alphabet is likely.

Important: I still need e-mails from Luke, Mark, and Thomas from the E period class, as well as Jackson, Marshall, Lloyd, David, Duncan, and Will from the F period class. Please see my contact information for the address.

 

M 9/14/09

HW due: Read §1.2 (reading notes required); write §1.2 #1-4 all, and write a short paragraph explaining why the following “solution” to §1.1 #13 is invalid. (Bonus: Can you find a valid solution?)



Note: I still need e-mails from Marshall and Will C.

 

T 9/15/09

HW due: Read §1.3 (reading notes required); write §1.3 #1, 3, 4, 6.

 

W 9/16/09

HW due: Read §1.4 (reading notes required); write §1.2 #5 (including part b, which was done in class), 9 (making a rough sketch for each one), §1.3 #8, 9, 13, 18. Note that problem #18 is not in the textbook but is given below.

18. Given: In , let AB = x and BC = y. (AB and BC refer to segment lengths, as opposed to  and , which refer to sets of points. In other words, we omit the segment bar if we are referring to a number.)

Find: strict lower and upper bounds for AC. Please make several diagrams to justify your answers.

(Note: The “strict lower bound” is the value that is less than any possible answer for AC. The “strict upper bound” is the value that is greater than any possible answer for AC. For example, in problem #13, the lower bound for AC was 3 and the upper bound for AC was 15. Obviously, your answers to #18 will need to have variables in them.)

 

Th 9/17/09

HW due: Read §1.5; write §1.4 #9, 10, 14, 15, convert 77.285 degrees to DMS (see example below), and play the Eyeballing Game until you are good at it. (This may take 10-15 minutes.) Write down your best score. My best score is 2.28, and you will probably not be able to beat that.

Example of DMS conversion, using the substitution principle:

38.808° = 38° + .808°
              = 38° + .808(60')
              = 38° + 48.48'
              = 38° + 48' + .48'
              = 38° + 48' + .48(60")
              = 38° + 48' + 28.8"
              = 38°48'28.8"

Another example:

16.118° = 16° + .118°
              = 16° + .118(60')
              = 16° + 7.08'
              = 16° + 7' + .08'
              = 16° + 7' + .08(60")
              = 16° + 7' + 4.8"
              = 16°07'04.8"

 

F 9/18/09

HW due: Convert 17°76'07.4" to decimal degrees. Yes, that is a very skimpy assignment. Use the rest of your time to clean up your older homework problems so that they are clear, complete, and in proper format.

 

M 9/21/09

HW due (strongly recommended): Spend 50 minutes on Sunday afternoon working on last year’s first test for practice. Set a timer for 50 minutes, put away your books, and try to take the test. We will grade these in class if most of the students did them. If you do not have time to take the practice test over the weekend, then do it on Monday night as part of your test preparation, but of course that may be a little too late.

HW due (required): Read §§1.7 and 1.8 (these were covered on Friday in E period but not in F period because of the larger number of questions in F period); write §1.5 #16, §1.7 #5a, 8, 10, §1.8 #1, 2, 4. This assignment is definitely longer than 35 minutes, but you need to do it. Several versions of §1.5 #13 are furnished below as graphic files to help you see what is expected in two-column proofs.

Sample proof #1
Sample proof #2
Sample proof #3

 

T 9/22/09

Test #1 (100 pts.) on all material covered in class up to this point, including the substitution principle, clock problems, the key to learning, the reason that schoolwork is graded, etc. To prepare for the test, please work the 50-minute practice test under time pressure, and then grade yourself using the scoring key.

Here are the answers to the HW problems we did not have time to cover during yesterday’s class:

2.(a) Original statement: If each side of a  has length 10, then the perimeter is 30. (TRUE)
        Converse: If the perimeter of a  is 30, then each side has length 10. (FALSE)
        Inverse: If some side of a  does not have length 10, then the perimeter is 30. (FALSE)
        Contrapositive: If the perimeter of a  is not 30, then some side does not have length 10. (TRUE)

Warning: Correctly negating a declarative sentence such as “Each side of a  has length 10” is not easy. For example, you should not say, “Each side of a  does not have length 10,” because the meaning is unclear. Do you mean that side x is not 10, side y is not 10, and side z is also not 10? Or do you mean that of the three sides, not all three of them are 10? What you mean is the latter, but that is not clear unless you use careful wording, as I have done above. You could also use the following correct but somewhat awkward wording: “It is not the case that all the sides are of length 10.”

The confusion is somewhat reminiscent of a classic Saturday Night Live sketch summarized in the first two paragraphs of this page. (Don’t read the rest of the link; it is irrelevant.)

   (b) Original statement: If an angle is acute, then it has a measure greater than 0 and less than 90. (TRUE)
        Converse: If an angle has measure greater than 0 and less than 90, then the angle is acute. (TRUE)
        Inverse: If an angle is not acute, then it does not have a measure greater than 0 and less than 90. (TRUE)
        Contrapositive: If an angle does not have a measure greater than 0 and less than 90, then the angle is not acute. (TRUE)

4. Let C = “A person is a Chicago resident.” Let I = “A person is an Illinois resident.”
    The diagram illustrates that  is a true statement.


   (a) Given that Penny lives in Chicago, can we conclude that Penny lives in Illinois? TRUE, since .
   (b) Given that Benny lives in Illinois, can we conclude that Benny lives in Chicago? FALSE, since that would be reasoning from the converse. We were not given that , only that .
   (c) Given that Kenny does not live in Chicago, can we conclude that Kenny lives in Illinois? FALSE, since he could live outside both regions shown in the Venn diagram.
   (d) Given that Denny does not live in Illinois, can we conclude that Denny lives in Chicago? FALSE. In fact, since the contrapositive of  is , precisely the opposite conclusion is true. We can conclude that Denny does not live in Chicago.

 

W 9/23/09

HW due: Read §2.1; write §2.1 #2, 3, 4, 8, 9, 11.

 

Th 9/24/09

HW due: Read §2.2; write §2.4 #12, §2.2 #3, 4, 6, 7, 11, 18, 19. You may find this entry from last year’s HW store helpful. (In fact, if you need to, I will give you permission to copy the solution to #12.)

Additional HW due (E period only): Correct your test, using a different color of ink and a separate sheet if necessary. If you do not finish by today, you may turn this in on Monday.

 

F 9/25/09

Centennial day of community service (no class). Arrive at school between 7:30 and 7:45 a.m. carrying a water bottle with your name on it. Lunch will be furnished.

 

M 9/28/09

HW due: Read §§2.3 and 2.4; write §2.3 #5, 6, 13, 14, §2.4 #1-7 all.

Also write corrections (using a different color of ink) for your test from last week. If there is insufficient room on the test paper itself, use a fresh sheet. Please write, “I should have . . .” or “I realize now that the method is to . . .” when you have figured out what the problem was asking you to do.

If you would like a fresh copy of the test, you can download an E period test or an F period test for additional practice.

For problem #12, the shortest (and in some sense, best) proofs were 3 steps long. These steps are reproduced below, with no reasons given. You will need to think of the correct reasons when you write up your corrections.

1. Angles BCA and BCD are right angles.
2. Angles BCA and BCD are congruent.
3. Ray CB bisects angle ACD. (Q.E.D.)

 

T 9/29/09

HW due: Nothing new, in theory. However, make your test corrections 100% neat and wonderful. They will be graded more closely this time. No shortcuts, no excuses. Work hard, be nice, and remember that there is no finish line. (I borrowed all these slogans from the KIPP School, but they are certainly applicable, don’t you think?)

With any remaining time that you have, patch up the holes and gaps in your previous homework assignments. Be prepared for a random spot-check covering previously assigned material.

 

W 9/30/09

HW due: Read §2.5; write §2.5 #1, 2, 4, 14, and the problem below.

20. Given: In the diagram, . What can we conclude, and why?

 

 


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Last updated: 07 Oct 2009