Stage: 5 Challenge Level: 
$A$ and $B$ are two fixed points on a circle and $RS$ is a variable diamater. What is the locus of the intersection $P$ of $AR$ and $BS$?
Manipulating algebraic expressions/formulae. Making and proving conjectures. Stage 5 - Reviewed 2012. Inequality/inequalities. Dynamic geometry. epsilons. Summation of series. alphas. Mathematical reasoning & proof. Circle theorems.
Published March 1999.
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