MathDB

3

Part of 1999 South africa National Olympiad

Problems(1)

Centre of (CKL) lies on (BCD)

Source: South Africa 1999

9/30/2005
The bisector of ∠BAD\angle{BAD} in the parallellogram ABCDABCD intersects the lines BCBC and CDCD at the points KK and LL respectively. Prove that the centre of the circle passing through the points C, KC,\ K and LL lies on the circle passing through the points B, CB,\ C and DD.
geometryparallelogramcircumcircletrigonometryratiogeometric transformationrotation