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National and Regional Contests
Ukraine Contests
Official Ukraine Selection Cycle
Kyiv City MO
Kyiv City MO - geometry
Kyiv City MO Juniors 2003+ geometry
2017.9.51
2017.9.51
Part of
Kyiv City MO Juniors 2003+ geometry
Problems
(1)
tangential quadrilateral by medians, isosceles (2017 Kyiv City MO 9.5.1)
Source:
9/8/2020
In the triangle
A
B
C
ABC
A
BC
, the medians
B
B
1
BB_1
B
B
1
and
C
C
1
CC_1
C
C
1
, which intersect at the point
M
M
M
, are drawn. Prove that a circle can be inscribed in the quadrilateral
A
C
1
M
B
1
AC_1MB_1
A
C
1
M
B
1
if and only if
A
B
=
A
C
AB = AC
A
B
=
A
C
.
geometry
tangential quadrilateral
Medians
isosceles