WOLFRAM|DEMONSTRATIONS PROJECT

Concurrence of the Median, a Chord and a Diameter of the Incircle

​
In the triangle
ABC
, let the incircle have center
I
and let its points of tangency to the sides
BC
,
CA
and
AB
be points
D
,
E
and
F
, respectively. Let
M
be the midpoint of
BC
. Then the lines
AM
,
EF
and
DI
are concurrent. Drag the locators
A
,
B
and
C
to see that this holds for any triangle.