All the articles have been derived by the author by using simple geometry & trigonometry. These articles are related to the analysis of the elliptical path in the annular region between two circle, smaller inside bigger one & their centers separated by a certain distance. These formula are used to calculate minor axis, major axis, eccentricity & the radius of the third tangent circle touching the smaller circle externally & the bigger one internally. These articles (formula) are very practical & simple to apply in case studies & practical applications of 2-D Geometry.