October 31, 2007...10:00 pm

4.1 Triangle Intoduction

What fun we had today! We started out Triangle Unit which will take us through the end of the semester. 4.1 Triangle introduction gave taught us how to classify triangles by angles (BM 21) and sides and the EXTREMELY important concept that all the angles in a triangle add up to 180 degrees (BM 19). The homework is #30 page 198 #10-15, 17-43 (odd), 57-62. We did play Me Vs. You and with each class winning, the actual homework assignments varied. Way to go!

Coming Up: Grade Reports and Chapter 3 Test on our next block!

Also, BM 19 and 21 on Triangles, as well as retakes for 15-17 on Monday!

Posting for points question:

This is an easy one. . . Give 2 angles of a triangle and find the third. Then classify the triangle by the angles and sides.

34 Comments

  • Um… 2x+14=180
    -14 -14
    2x=166
    _ _

    x=83

    Like that?

  • angle 1=70
    angle 2=40
    must equal 180
    angle 3= 70

    isosceles acute triangle

  • Gurpreet S. per.4

    angle 1=50

    angle 2=80 80+50=130

    180-130= 50

    angle 3=50

    acute isosceles

  • Angle 1=60

    Angle 2=80

    80+60=140

    180-140=40

    Angle 3=40

  • Angle #1= 50

    Angle #2= 600

    600+50=650

    180-650=470

    Angle#3= 470

    ;-)

    Mr. F adds: Isn’t 600 kind of big for an angle? Considering all 3 together can’t be more than 180! That 180-650 would actually be -470.

  • Angle 1 = 60º

    Angle 2 = 60º

    Triangle Sum Theorem: sum of the measures of the interior angles of a triangle is 180º

    Therefore: 60º+60º+x=180º
    120º+x=180º
    – 120º -120º
    _____________
    x= 60º

    Angle 3 = 60º

    Classified Angle:
    Acute Equiangular Equilateral Triangle

  • Rebecca K period 5

    5x + 15= 180º
    -15 -15

    5x=165
    — —
    5 5

    x=33

  • Angle 1= 24
    Angle 2= 12
    24+12+x=180
    36+x=180
    -36 – 36
    x=144

    Obtuse Scalene Triangle

  • Angle 1= 2x
    Angel 2= 3x
    90+2x+3x=180
    90+5x=180
    -90 -90
    5x=90
    x=18

    acute scalene triangle

  • Angle 1= 73

    Angle 2=62

    73+62=135
    180-135=55

    Angle 3=55

    Acute Iosceles Triangle

  • Angle 1=50
    Angle 2=90
    50+90=140
    180-140=40
    Angle 3=40

    Right scalene triangle

  • angle #1=70

    angle#2=40

    70+40+x=180

    130+x=180

    -130 -130

    x=50

    angle#3=50

    acute isoceles triangle

  • Angle#1=50

    Angle#2=80

    50+80+x=180
    50+80=130
    180-130=50
    acute isoceles triangle

  • Hey Mr.F I can’t believe I now have a 88% in this class. I didn’t really think I was going to pass the last three bm’s but I did yay!!! I’m looking foward to taking the next 2 and the test. wish me luck.

    P.S: I checked my g.r. and it says that i’m missing the transformation ws but i turned it in but i think i didn’t write a title on it.

  • angle#1

  • angle #1= 55
    angle #2=75

    55+75+x=180
    130+x=180
    x=50
    acute scalene triangle

  • angle 1=60

    angle 2=80

    80+60=140

    180-140= 40

    angle 3=40

    acute scalene

  • Angle#1- 66
    Angle#2-25
    Angle#3- x

    66+25+x=180

    91+x=180
    -91 -91
    x=89

    x

    acute scalene

  • Angle 1 = 50
    Angel 2 = 70

    50+70= 120

    180-120= 60 ACUTE SCALENE
    Angel 3 = 60

  • angles to find~
    angle 1. 73
    angle 2. 25
    angle 3. x
    73+25+x=180
    98+x=180
    -98
    x=82

    acute scalene

  • Angle 1=50
    Angle 2=90
    50+90=140
    180-140=40
    Angle 3=40

    Right scalene triangle

  • Angle 1-30
    Angle 2- X
    Angle 3- 120

    30+120+x=180
    150+x=180
    180-150=30
    X=30

    obtuse isoceles triangle

  • angle 1- 75
    angle 2-21
    angle 3-x

    75+21+x=180
    96+x=180
    -96 -96
    x=84

    acute scalene triangle

  • Angle #1-80 Degrees
    Angle #2-30 Degrees

    Angles must equal 180 Degrees

    80+30+x=180
    110+x=180
    x=70

    Angle #3-70 Degrees

    Isoceles Acute Triangle

  • Angle #1=40
    Angle #2=50
    40+50=90
    Angle #3=60 degrees
    scalene acute triangle

  • Angle #1 50
    Angle#2 60
    50+60+x=180
    110+x=180
    -110 -110
    x=70
    Isoceles Acute Triangle

  • angle 1: 37*
    angle 2: 69*
    37* + 69* + x=180*
    106* + x=180*
    -106* -106*
    X=74*
    scalene acute triangle

  • Angle #1=30
    Angle #2=40

    30+40+x=180
    70+x=180
    -70 -70
    x=110

    Obtuse scalene

  • Angle 1: 30 degrees
    Angle 2: 70 degrees
    Angle 3=80 degrees
    Type of triangle:
    Acute Scalene Triangle

  • angle 1= 30
    angle 2= 100
    all parts of a triangle must add up to 180 therefore:
    angle 3=50
    it is an obtuse scalene triangle

  • angle 1=24

    angle 2=54

    angle 3=x

    24+54+x=180
    80+x=180
    -80 -80
    x=100

    This triangle is an obtuse scalene triangle

  • Angle 1 =90
    Angle 2 = 45
    Angle 3 = 45

    due to the 90 degree angle the triangle is a right triangle

  • angle A= 64
    angle B=54
    must add up to 180 degrees
    180
    -64
    =118
    -54
    = 64
    angle C=64
    Obtuse Scalene Triangle

  • In triangle ABC
    <A = 36
    <B = 72
    Find < C, and then classify the triangle.

    As <A + <B + <C = 180, so
    <C = 180 – <A – <B = 180 – 36 – 72 = 72
    Thus triangle ABC is an Acute Isosceles Triangle.


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