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Monday, December 04, 2006

Monday, December 3, 2006
1st Block: lesson 3.1 Solving oblique triangles
Today's scribe is Natalie Berryhill

posted by Mrs. S. at 7:51 AM

2 Comments:

  • In Today's Lesson, 3.1A, we learned about AAS(Angle angle side) and ASA (Angle Side Angle).
    We learned that oblique trianges have NO right angles.
    The Law of Sines formula is (sorry about the division signs, Mrs. S)
    sinA/a= sinB/a= sinC/c or the reciprocal: a/sinA= b/sinB= c/sinC.
    We learned that SSA, AAS, and ASA triangles use the Law of Sines formula while SAS and SSS triangles use the Law of Cosines formula.
    In solving these oblique triangles,
    Step 1: Determine the case (AAS, ASA, SSS, SAS, SSA)
    Step 2: Solve using the appropriate law.
    Ex 1 from the powerpoint:
    Given: Triangle ABC where C= 102.3 degrees, B= 28.7 degrees, and b= 27.4 feet. Find the remaining sides and angles.
    To Solve:
    1. Draw the oblique triangle labeling A and B as the bottom angles and C as the top angle with a, b, and c being the opposite of their angles.
    2. Decide which case you are using (In this case, it is the AAS case)
    3. You are given two degrees, so find the third degree.
    (180 degrees - (28.7 +27.4) degrees=49 degrees, angle A)
    4. Find a or c. I found c. To do so, use the Law of Sines. c/sinC = b/sinB. When you put in the degrees and angles, you get c/sin102.3=27.4/sin28.7. Then, you multiply both sides by sin102.3 and come up with c=27.sin102.3/sin28.7. (Make sure your calculator is in DEGREES!!!!! That's VERY important!)You end up with c=55.7 feet.
    5. Now that you have found all but one side, you can use b/sinB or c/sinC to find a/sinA. Follow the same directions as in number 4 and your final answer should be 43.1 feet.
    Altogether, this is an easy lesson and shouldn't take long to do.
    The assignment is Pg. 280 (1-4)all (7-9)all and #36. Good luck! :)

    By Anonymous Anonymous, at 4:08 PM  

  • Sry, that's 7-10 all!!!

    By Anonymous Anonymous, at 4:11 PM  

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