 If "a" and "b" are coprime and "a" divides the product "bc", then "a" divides "c".This can be viewed as a generalization of Euclid's lemma.The two integers "a" and "b" are coprime if and only if the point with coordinates ("a", "b") in a Cartesian coordinate system is "visible" from the origin (0,0), in the sense that there is no point with integer coordinates on the line segment between the origin and ("a", "b").