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Problems
Contests
National and Regional Contests
Turkey Contests
National Olympiad First Round
2014 National Olympiad First Round
13
13
Part of
2014 National Olympiad First Round
Problems
(1)
P13 [Geometry] - Turkish NMO 1st Round - 2014
Source:
5/23/2014
Let
A
B
C
D
ABCD
A
BC
D
be a convex quadrilateral such that
m
(
A
D
B
^
)
=
1
5
∘
m \left (\widehat{ADB} \right)=15^{\circ}
m
(
A
D
B
)
=
1
5
∘
,
m
(
B
C
D
^
)
=
9
0
∘
m \left (\widehat{BCD} \right)=90^{\circ}
m
(
BC
D
)
=
9
0
∘
. The diagonals of quadrilateral are perpendicular at
E
E
E
. Let
P
P
P
be a point on
∣
A
E
∣
|AE|
∣
A
E
∣
such that
∣
E
C
∣
=
4
,
∣
E
A
∣
=
8
|EC|=4, |EA|=8
∣
EC
∣
=
4
,
∣
E
A
∣
=
8
and
∣
E
P
∣
=
2
|EP|=2
∣
EP
∣
=
2
. What is
m
(
P
B
D
^
)
m \left (\widehat{PBD} \right)
m
(
PB
D
)
?
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
A
)
<
/
s
p
a
n
>
1
5
∘
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
B
)
<
/
s
p
a
n
>
3
0
∘
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
C
)
<
/
s
p
a
n
>
4
5
∘
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
a
n
>
6
0
∘
<
s
p
a
n
c
l
a
s
s
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
a
n
>
7
5
∘
<span class='latex-bold'>(A)</span>\ 15^{\circ} \qquad<span class='latex-bold'>(B)</span>\ 30^{\circ} \qquad<span class='latex-bold'>(C)</span>\ 45^{\circ} \qquad<span class='latex-bold'>(D)</span>\ 60^{\circ} \qquad<span class='latex-bold'>(E)</span>\ 75^{\circ}
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
A
)
<
/
s
p
an
>
1
5
∘
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
B
)
<
/
s
p
an
>
3
0
∘
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
C
)
<
/
s
p
an
>
4
5
∘
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
D
)
<
/
s
p
an
>
6
0
∘
<
s
p
an
c
l
a
ss
=
′
l
a
t
e
x
−
b
o
l
d
′
>
(
E
)
<
/
s
p
an
>
7
5
∘
geometry