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Mathematics
Mathematics
Problem
In
△
A
B
C
\triangle ABC
△
A
B
C
, side
B
C
BC
B
C
is produced to point
D
D
D
. Prove that
∠
A
C
D
=
∠
A
+
∠
B
\angle ACD = \angle A + \angle B
∠
A
C
D
=
∠
A
+
∠
B
.
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