Triangle Theorems
Triangle Theorems180 is leany triang of sum angle The
A
B
C
Triangle Theorems180 is leany triang of sum angle The
180 sum 180 ABCCBA
A
B
C
Triangle Theorems180 is leany triang of sum angle The
180 sum 180 ABCCBA
A
B
C
Proof:
Triangle Theorems180 is leany triang of sum angle The
180 sum 180 ABCCBA
A
B
C
Proof:Construct DE||BC passing through A
D
E
Triangle Theorems180 is leany triang of sum angle The
180 sum 180 ABCCBA
A
B
C
Proof:Construct DE||BC passing through A
D
E
BCDEABCDAB ||,s'alternate
Triangle Theorems180 is leany triang of sum angle The
180 sum 180 ABCCBA
A
B
C
Proof:Construct DE||BC passing through A
D
E
BCDEABCDAB ||,s'alternate
BCDEACBEAC ||,s'alternate
Triangle Theorems180 is leany triang of sum angle The
180 sum 180 ABCCBA
A
B
C
Proof:Construct DE||BC passing through A
D
E
BCDEABCDAB ||,s'alternate
BCDEACBEAC ||,s'alternate
180straight 180 DAECAEBACDAB
Triangle Theorems180 is leany triang of sum angle The
180 sum 180 ABCCBA
A
B
C
Proof:Construct DE||BC passing through A
D
E
BCDEABCDAB ||,s'alternate
BCDEACBEAC ||,s'alternate
180straight 180 DAECAEBACDAB180 ACBBACABC
A
B
CD
A
B
CD
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
A
B
CD
CABBAACD ,exterior
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
A
B
CD
CABBAACD ,exterior
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
Proof:
A
B
CD
CABBAACD ,exterior
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
Proof:Construct CE||BA
E
A
B
CD
CABBAACD ,exterior
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
Proof:Construct CE||BA
BACEECDABC ||,s'ingcorrespond
E
A
B
CD
CABBAACD ,exterior
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
Proof:Construct CE||BA
BACEECDABC ||,s'ingcorrespond
E
BACEACEBAC ||,s'alternate
A
B
CD
CABBAACD ,exterior
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
Proof:Construct CE||BA
BACEECDABC ||,s'ingcorrespond
E
BACEACEBAC ||,s'alternate
common ECDACEACD
A
B
CD
CABBAACD ,exterior
The exterior angle of any triangle is equal to the sum of the two opposite interior angles
Proof:Construct CE||BA
BACEECDABC ||,s'ingcorrespond
E
BACEACEBAC ||,s'alternate
common ECDACEACD
BACABCACD
Polygon TheoremsA B
CD
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBA
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof:
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof:
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
540 sum 540 ABCDEEDCBA
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
540 sum 540 ABCDEEDCBAProof:
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
540 sum 540 ABCDEEDCBAProof:
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
540 sum 540 ABCDEEDCBAProof: 180sum ABE
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
540 sum 540 ABCDEEDCBAProof: 180sum ABE
180sum BED
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
540 sum 540 ABCDEEDCBAProof: 180sum ABE
180sum BED(+)
180sum BDC
Polygon TheoremsA B
CD
360 is ralquadrilateany of sum angle The
360 sum 360 ABCDDCBAProof: 180sum ABC
180sum ADC(+)
360sum ABCD
A
B
C
DE
540 ispentagon any of sum angle The
540 sum 540 ABCDEEDCBAProof: 180sum ABE
180sum BED(+)
540sum ABCDE
180sum BDC
sidesofnumber theis where
,2180 ispolygon any of sum angle Then
n-
sidesofnumber theis where
,2180 ispolygon any of sum angle Then
n-
a
b
cd
e
sidesofnumber theis where
,2180 ispolygon any of sum angle Then
n-
a
b
cd
e
360 ispolygon any ofsumangleexterior The
sidesofnumber theis where
,2180 ispolygon any of sum angle Then
n-
a
b
cd
e
360 ispolygon any ofsumangleexterior The
360sum exterior 360 edcba
sidesofnumber theis where
,2180 ispolygon any of sum angle Then
n-
a
b
cd
e
360 ispolygon any ofsumangleexterior The
360sum exterior 360 edcba
Exercise 8B; 1dg, 2c, 3dh, 5ace, 6ab (iii), 7b, 8bfh, 9ad, 10dh,11ad, 12c, 16, 18, 20
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