Classify Triangles Foldable.notebook
Angle
Acute
Right
Obtuse
Equiangular
November 19, 2012
Side
Scalene
Isoscele
s
Equilatera
l
1
Classify Triangles Foldable.notebook
November 19, 2012
Cut out the large triangle
Do NOT crumble scraps!!
From your scraps cut out another triangle of any type as large as you can make it.
2
Classify Triangles Foldable.notebook
November 19, 2012
From the scrap triangle ­ put a different number of dots in each angle.
3
Classify Triangles Foldable.notebook
November 19, 2012
Tear off two of the angles
4
Classify Triangles Foldable.notebook
November 19, 2012
Like a puzzle, fit the three angles together using the straight sides.
What happens? Can you make a conjecture about the sum of the 3 angles of a triangle?
5
Classify Triangles Foldable.notebook
November 19, 2012
180o
Triangle Sum Theorem: The sum of the interior angles of ANY triangle is 180o.
6
Classify Triangles Foldable.notebook
November 19, 2012
Using the large triangle cut out earlier:
Fold the three points of the triangle to the inside.
Fol
d
Fol
d
Fold
7
Classify Triangles Foldable.notebook
Turn it over.
Write the Title in the middle.
November 19, 2012
Classifying
Triangles
8
Classify Triangles Foldable.notebook
November 19, 2012
Turn it over.
On the first flap, Acute write....
Scalene
)))
))
)))
all angles <90o
no ≅ sides or angles
Classifying
Triangles
9
no ≅ sides or angles
Classify Triangles Foldable.notebook
Classifying
Triangles
November 19, 2012
Right Scalene
)
On the bottom right, write....
))
one angle = 90o
the two acute angles are complementary
no ≅ sides or angles
10
no ≅ sides or angles
Classify Triangles Foldable.notebook
On the bottom left write....
Obtuse Scalene
Classifying Right Triangles
Scalene
))
)
November 19, 2012
)))
one OBTUSE angle 2 acute angles
no ≅ sides or angles
)
))
one angle = 90
the two acute angles ar
complementary
no ≅ sides or ang
11
Classify Triangles Foldable.notebook
November 19, 2012
Turn the triangle over and make sure that the center triangle points South.
)
etucA
enelacS
)
)
)))
09< selgna lla
selgna ro sedis ≅ on
o
thgiR
enelacS
esutbO
enelacS
))
)
)
))
09 = elgna eno
o
)) )
elgna ESUTBO eno
selgna etuca 2
era selgna etuca owt eht
yratnemelpmoc
selgna ro sedis ≅ on
selgna ro sedis ≅ on
12
)
))
Classify Triangles Foldable.notebook
November 19, 2012
09 = elgna eno
o
In the center triangle, write...
era selgna etuca owt eht
yratnemelpmoc
selgna ro sedis ≅ on
)
)
)))
)) )
et
e ucA
n
e
l
a
c
S
60o
))
o
se 09<
l
g
n se
a
ro lgn
s
ed a lla
i
s
≅
o
n
3≅ sides &
3 ≅ angles
es
e utb
n
e
l O
a
c
S
)
≅
o
n
o s
e a 2
d
i
s
n
a
r
e
l
g
))
n
a E
sel selgn SUT
B
g
a
e
t O u
e
n
c
o
)60oEquiangular )o
60
Equilateral
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Classify Triangles Foldable.notebook
November 19, 2012
Acute Isosceles
Vertex angle
leg
))
In the top triangle, write...
leg
)
)
base
all angles < 90o
2 ≅ sides 2 ≅ angles
)60 Equiangular 60)
Equilateral
)
)
et
e ucA
n
e
l
a
c
S
60o
))
es
ene utbO
l
a
cS
)))
)
))
o
09
s
e
l
g < se
n
a
r lgn
o
se a lla
d
i
s ≅
on
e
l
g
na
s ES
se elg UT
l
g
na na e BO
ro tuc en
s
ed a 2 o
n
is
≅
o
3≅ sides &
3 ≅ angles
)))
o
o
14
)
November 19, 2012
all angles < 90
2 ≅ sides 2 ≅ angles
o
)
)
))
one OBTUSE angle 2 ≅ sides 2 acute ≅ angles
et
en ucA
e
l
a
c
S
3≅ sides &
3 ≅ angles
)
))
)
Equiangular )
Equilateral
o
sel 09< g
n
a sel
r
o gna
l
s
l
e
a
d
i
s
≅
o
n
)
In the bottom left
Obtuse triangle, Isosceles
write...
)))
Classify Triangles Foldable.notebook
P. 198 #6­26
15
2 ≅ sides 2 ≅ angles
Classify Triangles Foldable.notebook
November 19, 2012
) Equiangular )
Equilateral
Right
btuse TUSE angle Isosceles
)
))
)
3≅ sides &
3 ≅ angles
))
)
ONE angle = 90 o
)
osceles
In the bottom right
triangle, write...
2 acute ≅ angles
2 ≅ sides 2 ≅ angles (45o )
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Classify Triangles Foldable.notebook
November 19, 2012
Acute Scalene
)
)) )
)
all angles <90o
no ≅ sides or angles
))
)
)) )
one OBTUSE angle 2 acute angles
no ≅ sides or angles
Right Scalene
)
)
all angles < 90o
2 ≅ sides 2 ≅ angles
))
) 60 Equiangular60)
one angle = 90o
the two acute angles are complementary
no ≅ sides or angles
)
o
o
Obtuse Isosceles
)
3≅ sides &
3 ≅ angles
Right
Isosceles
ONE )
))
)
Equilateral
))
)
angle = 90
one OBTUSE angle 60o
2 ≅ sides 2 acute ≅ angles 2 ≅ sides 2 ≅ angles (45o )
o
)
Classifying
Triangles
))
Obtuse Scalene
Acute Isosceles
17
Classify Triangles Foldable.notebook
November 19, 2012
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