The present paper contains further extensions of results given in [1], and includes another family of curves called N-power ellipses which are a generalization of the notions of ellipses, Cassini ovals and Fermat curves. We examine the chordal condition introduced in [1] of N-power ellipses at a fixed point, for natural and rational values of N. Next we formulate and prove the chordal condition for an ellipse, for an arbitrary point lying inside of it. The chordal condition is a generalization of a well-known property of ellipses, expressing relations of lengths from their foci to other points. This paper is based on Stewart’s theorem [5–7].