prove that a chord is tangent to the incircle
by ihategeo_1969, Mar 23, 2025, 9:01 PM
Let 
be a triangle with incenter 
and intouch triangle 
. Let 
be the foot of the perpendicular from 
onto 
. Assume that 
, 
intersect the sides 
, 
in 
respectively. Finally, let the rays 
, 
meet the circumcircle of 
in 
, 
respectively. Prove that the tangent from to the incircle and the line 
meet on the circumcircle of .
Proposed by Aditya Khurmi
be a triangle with incenter 
and intouch triangle 
. Let 
be the foot of the perpendicular from 
onto 
. Assume that 
, 
intersect the sides 
, 
in 
respectively. Finally, let the rays 
, 
meet the circumcircle of 
in 
, 
respectively. Prove that the tangent from to the incircle and the line 
meet on the circumcircle of .Proposed by Aditya Khurmi
This post has been edited 1 time. Last edited by ihategeo_1969, 2 hours ago
.
and 
intersect at 
.
be the midpoint of 
.
is chosen on the extension of 
beyond 
is chosen on the segment 
such that 
.
and 
.
bisects 
.
satisfying 
and their sum is an even number, consider the quadratic polynomial:![\[
P(x) = x^2 - (m^2 - m + 1)x + (m^2 - n^2 - m)(n^2 + 1).
\]](http://latex.artofproblemsolving.com/d/5/1/d51aaddfddfe06cc91abfdd3476a155770a8a5fd.png)
are positive integers but are not perfect squares.
and 
,
such that![\[
ad = bc, \quad a + d = 2^k, \quad b + c = 2^m
\]](http://latex.artofproblemsolving.com/1/1/d/11d16732e3a77af46ad17adecf104a442a5d7f67.png)
for some positive integers 
and 
.
.
be the points where the incircle touches the sides 
respectively. Let 
meet the line 
respectively. Further assume that both 
are outside the triangle 
are concyclic.
.
such that 
is a perfect square but none of the integers 
are perfect squares.
lie respectively on sides 
.
and 
and 
cross again at point 
different from 
.
be a triangle with circum-circle 
.
be a point in the interior of triangle 
.
meet 
respectively. Suppose 
is the point of intersection of 
with 
;
is the point of intersection of 
with 
.
is parallel to 
.
July 2014
June 2014