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Problems
Mathematics
Mathematics
Problem
In
△
A
B
C
\triangle ABC
△
A
B
C
, side
B
C
BC
B
C
is produced to a point
D
D
D
. If
∠
A
=
40
∘
\angle A = 40^{\circ}
∠
A
=
4
0
∘
and the exterior angle
∠
A
C
D
=
110
∘
\angle ACD = 110^{\circ}
∠
A
C
D
=
11
0
∘
, calculate
∠
B
\angle B
∠
B
.
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