It has been estimated that 1000 curies of a radioactive substance

[Dusty Huggins]

introduced at a point on the surface of the? It has been estimated that 1000 curies of a radioactive substance introduced at a point on the surface of the open sea would spread over an area of 30,000 km2 in 30 days. Assuming that the area covered by the radioactive substance is a linear function of time t and is always circular in shape, express the radius r (in km) of the contamination as a function of t (in days). Find the symbol ? in the MathPad symbol drawer or type pi.