to aspect ratios of general compact sets in a d-dimensional space: The diameter-width aspect ratio (DWAR) of a compact set is the ratio of its diameter to its width. A circle has the minimal DWAR which is 1. A square has a DWAR of . The cube-volume aspect ratio (CVAR) of a compact set is the d-th root of the ratio of the d-volume of the smallest enclosing axes-parallel d-cube, to the set's own d-volume. A square has the minimal CVAR which is 1. A circle has a CVAR of . An axis-parallel rectangle of width W and height H, where W>H, has a CVAR of . If the dimension d is fixed, then all reasonable definitions of aspect ratio are equivalent to within constant factors. Notations Aspect ratios are mathematically expressed as x:y (pronounced "x-to-y"). Cinematographic aspect ratios are usually denoted as a (rounded) decimal multiple of width vs unit height, while photographic and videographic aspect ratios are usually defined and denoted by whole number ratios of width to height. In digital images there is a subtle distinction between the display aspect ratio (the image as displayed) and the storage aspect ratio (the ratio of pixel dimensions); see Distinctions. See also Axial ratio Ratio Equidimensional ratios in 3D List of film formats Squeeze mapping Scale (ratio) Vertical orientation References Ratios