A semicircle with three tangents. The tangency points are shown. Prove that the red line segments are concurrent.
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Both the intersection point of red diagonals and the tangent point on the circle have the same horizontal distance to the perpendicular tangent on the left. Hence a perpendicular line from tangent point to the diameter goes through the intersection point.
Spoken by the oppressed people
A warning for the enemy
To stop the dictators
And prevent death
To avoid civil suffering