Sunday, October 14, 2012

Math Journal 10/14/12


Describe your understanding of the Triangle Sum Theorem. What does it say about the angles of a triangle? How can you use the Triangle Sum Theorem to prove 3 angle measurements are the angles of a triangle? Can the theorem be used to prove that 3 angle measurements are not the angles of a triangle? Apply your understanding of the Triangle Sum Theorem to answer the following scenario. 

Triangle LMN is an obtuse triangle and m < L = 25 degrees. m < M is the obtuse angle, and its measure in degrees is a whole number. What is the largest m < N can be to the nearest whole degree?

2 comments:

  1. The Triangle Sum Theorem is when the three angles in a triangle form a straight angle of 180 Degrees. You can use it to identify if it's the angles of a triangle by adding all the angles up; it has to equal 180 Degrees. A formula that's used for this is: a+b+c=180 Degrees. The theorem can be used to prove 3 angle measurements are not the angles of a triangle by using the formula; if it's not 180 Degrees then it isn't a triangle.

    Scenario Answer:

    The most Angle N would be is 65 Degrees, because an obtuse triangle has a right angle on the 180 Degree line so M would equal 90 Degrees. When you add 65+25+90, you get 180 Degrees.

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  2. Excellent Response Daniel! You demonstrated your understanding of the theorem using what we discussed in class. My only suggestion would be to make your statement stronger: for example "you can use it to identify if it's a triangle.." could have been written as, "you can use the triangle sum theorem to prove that the angles of a figure can be the measures of a triangle by..." Be sure to include a conclusion to your writing. Also, remember that an obtuse angle has to be GREATER than 90 degrees, ie: 91 degrees. This would make angle N 64 degrees at most!

    Introduce a topic and
    organize ideas - 3

    Develop the topic with
    evidence - 4

    Use appropriate and varied
    transitions to create cohesion -3

    Use domain-specific
    vocabulary to explain the
    topic - 4

    Establish and maintain a
    formal style and objective tone - 4

    Provide a conclusion - 3

    21/24 = 88% (level 3)

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