Name___________________________________
6.5 WS - Isosceles Triangles
Date________________ Period____
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Find the value of x.
2)
1)
6
x
x
8
3)
4)
x
32°
x
77°
5)
6)
2x − 1
7
x−1
6
7)
8)
x
x
26°
116°
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-1-
Worksheet by Kuta Software LLC
9)
10)
72°
x
70°
x
11)
12)
8
x + 14
12
13) m 2 = 17 x + 10
2x − 6
14) m 2 = 70 + x
2
2
77°
129°
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-2-
Worksheet by Kuta Software LLC
Name
Date
Period
Isosceles Triangles Worksheet
1. The vertex angle of an isosceles triangle is 40 . What is the measure of one
base angle?
Base Angle:
2. One base angle of an isosceles triangle is 73 . What is the measure of the
vertex angle?
Vertex Angle:
3. The degree measure of the vertex angle is (7x - 27) . The degree measure for
each base angle is (9x - 34) . What is the value of one base angle?
Base Angle:
4. The ratio of the measure of a base angle in an isosceles triangle to the measure
of the vertex angle is 2:16. Find the measure of each angle.
Base Angle:
Vertex Angle:
5. The degree measure of the vertex angle is (3x - 8) . The degree measure for
each base angle is (6x - 41) . What is the value of vertex angle?
Vertex Angle:
6. The ratio of the measure of a base angle in an isosceles triangle to the measure
of the vertex angle is 1:7. Find the measure of each angle.
Base Angle:
7. m CBD m CDB
m ABC 137
m DCE x
Vertex Angle:
E
C
A
B
D
x=
8. BD DE
m DEF 4 5x
m DBE 7 x 76
D
A
B
E
x=
F
9. BD DE
m DEB 2 x 5 y
m DBA 25 x 10 y
m CDE
50
C
D
x=
B
A
E
F
10. BC DC
C
144
x2 – x
B
x=
D
Bonus: BD DE
m ABD 10 12 x
m BDE x 93
D
x=
A
B
E
F
y=