Triangle-Exterior Angle - Math Worksheets for Kids

Triangle-Exterior Angle
The measure of an exterior angle of a triangle is equal to sum of the measures of opposite interior angles.
A
Exterior angle : ∠ACX
350
Opposite interior angles : ∠A and ∠B
Exterior angle = Sum of opposite interior angles
∠ACX = ∠A + ∠B
∠ACX = 1000 + 350
1000
B
C
∠ACX = 1350
X
Find the unknown exterior angle for each triangle.
E
1)
2)
3)
X
B
V
400
400
X
F
500
T
700
500
G
C
U
∠EFX =
∠TVX =
400
D
∠BDX =
P
4)
F
300
D
5)
X
X
6)
450
W
400
E
450
X
∠EFX =
Q
8)
J
U
V
∠VWX =
9)
A
X
350
K
R
650
P
350
400
L
∠KJX =
X
B
∠ABX =
Printable Math Worksheets @ www.mathworksheets4kids.com
550
450
R
∠PQX =
X
7)
X
C
∠QRX =
350
Q
Answer key
The measure of an exterior angle of a triangle is equal to sum of the measures of opposite interior angles.
A
Exterior angle : ∠ACX
350
Opposite interior angles : ∠A and ∠B
Exterior angle = Sum of opposite interior angles
∠ACX = ∠A + ∠B
∠ACX = 1000 + 350
1000
B
C
∠ACX = 1350
X
Find the unknown exterior angle for each triangle.
E
1)
2)
3)
X
B
V
400
400
X
∠EFX =
F
500
T
700
500
G
C
U
1100
∠TVX =
1000
400
D
∠BDX =
800
P
4)
F
300
D
5)
X
X
6)
450
450
X
700
Q
∠PQX =
X
7)
W
400
E
∠EFX =
550
450
R
U
900
8)
J
V
∠VWX =
1000
9)
A
X
350
K
R
650
P
350
350
400
L
∠KJX =
X
1050
X
B
∠ABX =
C
1250
Printable Math Worksheets @ www.mathworksheets4kids.com
∠QRX =
700
Q

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