The graph between $$\dfrac{1}{u}$$ and $$\dfrac{1}{v}$$ for a thin convex lens in order to determine its focal length is plotted as shown in the figure. The refractive index of lens is $$1.5$$ and its both the surfaces have same radius of curvatures $$R$$. The value of $$R$$ will be ______ cm. (Where $$u$$ = object distance, $$v$$ = image distance)