The concept of analytic geometry, i.e., the reciprocal transformation of geometry and algebra, hints a prospect for the reciprocal transformation of the "path problem" and the "time float problem". A reciprocal transformation can be used to solve a complex problem in one field by translating it into a simpler one in another field. In this case, owing to the generalized concept of length, various types of non-path problems such as the optimum allocation problem and equipment replacement problem can be represented as "path problems". A "length network", which is generalized in nature, is translated into a "time network" by changing the meanings of arcs and lengths. Furthermore, "path problems" can be represented as "time float problems" by discovering the relationships of paths in the length network and time floats in the time network. Base on the relationships, "time float problems" also can be represented as "path problems". The relationships are keys to updating the mutual correspondence of path problems and time float problems. The relationships mirror the uniform qualities of networks in various disciplines and fields. We apply such relationships to solve optimum allocation problems, equipment replacement problems, and path problems with required lengths and to analyze anomalies in projects under generalized precedence relations. These applications test the effectiveness of our proposed approach to theoretical and applied researches in various disciplines and fields.