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.
Mr. F\'s Geometry Blog 2007-2008 
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
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
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.