Inconsistent systems arise often in applications. Scientists try to find a functional relationship between variables. They collect data, which usually involve experimental error and by studying this data or from other findings, they suggest a mathematical model for it, ``functional relationship between variables." Because of the measurement error, usually a polynomial that passes through all The given points is not the a true representation of the relationship between variable. A lower degree polynomial may represent the relationship better. To find coefficients of such polynomial the method introduced in LAB 5 is useful. But most of the times this method gives us an inconsistent system, which requires an approximation. In this laboratory we discuss such approximation, `` Least Square Solution ".