MathDB
Problems
Contests
Undergraduate contests
VTRMC
2013 VTRMC
Problem 2
Problem 2
Part of
2013 VTRMC
Problems
(1)
maximize angle in triangle, side equality given
Source: VTRMC 2013 P2
5/13/2021
Let
A
B
C
ABC
A
BC
be a right-angled triangle with
∠
A
B
C
=
9
0
∘
\angle ABC=90^\circ
∠
A
BC
=
9
0
∘
, and let
D
D
D
be on
A
B
AB
A
B
such that
A
D
=
2
D
B
AD=2DB
A
D
=
2
D
B
. What is the maximum possible value of
∠
A
C
D
\angle ACD
∠
A
C
D
?
geometry
Triangle