Physicss Help.. ^_^ thnkss - calculate distance ball travels around curve b4 it dropss------??

Mike Harris stands at the very top of the sky dome stadium roof to pitch the opening ball for the Blue Jays game. He slips a bit left to centre and slides down along the frictionless roof surface. For what distance, measured along the curve, will he slide before leaving the roof? Assume the roff has a circular cross section of radius 125m.