Algebraic concepts may be used in defining elements of geometry, and geometric concepts may be used in defining elements of algebra. These alternatives, along with discussions of the use of algebra in teaching geometry† and the use of geometry in teaching algebra, should not be considered as creating a problem similar to the proverbial problem of the chicken and the egg. Rather they indicate how the interdependence of algebra and geometry may be used to improve the presentation and understanding of both subjects in terms of fundamental concepts of mathematics.