MathDB
Problems
Contests
Undergraduate contests
Putnam
1965 Putnam
A1
A1
Part of
1965 Putnam
Problems
(1)
Putnam 1965 A1
Source:
6/5/2008
Let
A
B
C
ABC
A
BC
be a triangle with angle
A
<
A <
A
<
angle
C
<
9
0
ā
<
C < 90^\circ <
C
<
9
0
ā
<
angle
B
B
B
. Consider the bisectors of the external angles at
A
A
A
and
B
B
B
, each measured from the vertex to the opposoite side (extended). Suppose both of these line-segments are equal to
A
B
AB
A
B
. Compute the angle
A
A
A
.
Putnam
college contests