MathDB
Problems
Contests
Undergraduate contests
Putnam
1977 Putnam
B2
B2
Part of
1977 Putnam
Problems
(1)
Putnam 1977 B2
Source:
4/7/2022
Given a convex quadrilateral
A
B
C
D
ABCD
A
BC
D
and a point
O
O
O
not in the plane
A
B
C
D
ABCD
A
BC
D
, locate point
A
′
A'
A
′
on line
O
A
,
OA,
O
A
,
point
B
′
B'
B
′
on the line
O
B
OB
OB
, point
C
′
C'
C
′
on line
O
C
,
OC,
OC
,
and point
D
′
D'
D
′
on line
O
D
OD
O
D
so that
A
′
B
′
C
′
D
′
A'B'C'D'
A
′
B
′
C
′
D
′
is a parallelogram.
college contests