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ISI B.Math Entrance Exam
2006 ISI B.Math Entrance Exam
7
B.Math - geometry
B.Math - geometry
Source:
June 17, 2012
geometry
angle bisector
geometry proposed
Problem Statement
In a triangle
A
B
C
ABC
A
BC
,
D
D
D
is a point on
B
C
BC
BC
such that
A
D
AD
A
D
is the internal bisector of
∠
A
\angle A
∠
A
. Now Suppose
∠
B
\angle B
∠
B
=
2
∠
C
2\angle C
2∠
C
and
C
D
=
A
B
CD=AB
C
D
=
A
B
. Prove that
∠
A
=
7
2
0
\angle A=72^0
∠
A
=
7
2
0
.
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