MathDB

1

Part of 1999 Switzerland Team Selection Test

Problems(1)

tangent to first circle at A is parallel to BC

Source: Switzerland - Swiss TST 1999 p1

2/19/2020
Two circles intersect at points MM and NN. Let AA be a point on the first circle, distinct from M,NM,N. The lines AMAM and ANAN meet the second circle again at BB and CC, respectively. Prove that the tangent to the first circle at AA is parallel to BCBC.
intersecting circlestangentparallelgeometry