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Contests
National and Regional Contests
USA Contests
MAA AMC
AMC 12/AHSME
1994 AMC 12/AHSME
29
29
Part of
1994 AMC 12/AHSME
Problems
(1)
1994 AMC 12 #29
Source:
12/30/2011
Points
A
,
B
A, B
A
,
B
and
C
C
C
on a circle of radius
r
r
r
are situated so that
A
B
=
A
C
,
A
B
>
r
AB=AC, AB>r
A
B
=
A
C
,
A
B
>
r
, and the length of minor arc
B
C
BC
BC
is
r
r
r
. If angles are measured in radians, then
A
B
/
B
C
=
AB/BC=
A
B
/
BC
=
[asy] draw(Circle((0,0), 13)); draw((-13,0)--(12,5)--(12,-5)--cycle); dot((-13,0)); dot((12,5)); dot((12,-5)); label("A", (-13,0), W); label("B", (12,5), NE); label("C", (12,-5), SE); [/asy]
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
A
)
<
/
s
p
a
n
>
1
2
csc
1
4
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
B
)
<
/
s
p
a
n
>
2
cos
1
2
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
C
)
<
/
s
p
a
n
>
4
sin
1
2
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
a
n
>
csc
1
2
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
a
n
>
2
sec
1
2
<span class='latex-bold'>(A)</span>\ \frac{1}{2}\csc{\frac{1}{4}} \qquad<span class='latex-bold'>(B)</span>\ 2\cos{\frac{1}{2}} \qquad<span class='latex-bold'>(C)</span>\ 4\sin{\frac{1}{2}} \qquad<span class='latex-bold'>(D)</span>\ \csc{\frac{1}{2}} \qquad<span class='latex-bold'>(E)</span>\ 2\sec{\frac{1}{2}}
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
A
)
<
/
s
p
an
>
2
1
csc
4
1
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
B
)
<
/
s
p
an
>
2
cos
2
1
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
C
)
<
/
s
p
an
>
4
sin
2
1
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
an
>
csc
2
1
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
an
>
2
sec
2
1
trigonometry
AMC