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National and Regional Contests
India Contests
India National Olympiad
2000 India National Olympiad
4
One on quads
One on quads
Source: INMO 2000 Problem 4
October 10, 2005
trigonometry
geometry
Pythagorean Theorem
geometry unsolved
Problem Statement
In a convex quadrilateral
P
Q
R
S
PQRS
PQRS
,
P
Q
=
R
S
PQ =RS
PQ
=
RS
,
(
3
+
1
)
Q
R
=
S
P
(\sqrt{3} +1 )QR = SP
(
3
+
1
)
QR
=
SP
and
∠
R
S
P
−
∠
S
Q
P
=
3
0
∘
\angle RSP - \angle SQP = 30^{\circ}
∠
RSP
−
∠
SQP
=
3
0
∘
. Prove that
∠
P
Q
R
−
∠
Q
R
S
=
9
0
∘
.
\angle PQR - \angle QRS = 90^{\circ}.
∠
PQR
−
∠
QRS
=
9
0
∘
.
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