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Mathematics
Problem
'I' is the incentre of
Δ
A
B
C
\Delta ABC
Δ
A
B
C
whose corresponding sides are
a
,
b
,
c
a, b, c
a
,
b
,
c
respectively.
a
I
A
+
b
I
B
+
c
I
C
a\mathbf{IA} + b\mathbf{IB} + c\mathbf{IC}
a
IA
+
b
IB
+
c
IC
is always equal to a. 0 b.
(
a
+
b
+
c
)
B
C
(a + b + c)\mathbf{BC}
(
a
+
b
+
c
)
BC
c.
(
a
+
b
+
c
)
A
C
(a + b + c)\mathbf{AC}
(
a
+
b
+
c
)
AC
d.
(
a
+
b
+
c
)
A
B
(a + b + c)\mathbf{AB}
(
a
+
b
+
c
)
AB
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