Let △ABC be an acute angle triangle and ω be its circumcircle. Let N be a point on arc AC not containing B and S be a point on line AB. The line tangent to ω at N intersects BC at T, NS intersects ω at K. Assume that ∠NTC=∠KSB. Prove that CK∥AN∥TS. geometrycyclic quadrilateralAngle Chasing