Spatial Localization Problem and the Circle of Apollonius

The Circle of Apollonius is named after the ancient geometrician Apollonius of Perga. This beautiful geometric construct can be helpful when solving some general problems of mathematical physics, optics and electricity. Here we discuss its applications to the 'source localization' problems, e.g. pinpointing a radioactive source using the set of Geiger counters. The Circles of Apollonius help analyze these problems in transparent and intuitive manner. This discussion can be useful for High School Physics and Math curriculum.