MathDB
A right angled triangle with AC=2AB

Source: Iran Team selection test 2024 - P2

May 19, 2024
geometry

Problem Statement

For a right angled triangle ABC\triangle ABC with A=90\angle A=90 we have AC=2ABAC=2AB. Point MM is the midpoint of side BCBC and II is incenter of triangle ABC\triangle ABC. The line passing trough MM and perpendicular to BIBI intersect with lines BIBI and ACAC at points HH and KK respectively. If the semi-line IKIK cuts circumcircle of triangle ABC\triangle ABC at FF and SS be the second intersection point of line FHFH with circumcircle of triangle ABC\triangle ABC , then prove that SMSM is tangent to the incircle of triangle ABC\triangle ABC.
Proposed by Mahdi Etesami Fard