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Mathematics — Applications And Interp.
Mathematics — Applications and Interp.
Problem
A convex quadrilateral
A
B
C
D
ABCD
A
B
C
D
has side lengths
A
B
=
5
AB=5
A
B
=
5
,
B
C
=
6
BC=6
B
C
=
6
,
C
D
=
7
CD=7
C
D
=
7
, and
D
A
=
8
DA=8
D
A
=
8
. It is known that the sum of
cos
A
\cos A
cos
A
and
cos
C
\cos C
cos
C
is zero. Determine the area of the quadrilateral.
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