SCSS: Common proportions

Coomon-proportions.scss

/*
Frequently used proportions:
Square:    1:1    -> 1           -> 100%   example: 400x400px      
Portrait:  4:3    -> 1.333...:1  -> 75%    example: 800x600px 
Divine:    5:3~   -> 1.618:1     -> 61.8%  example: 1110x686px 
Landscape: 16:9   -> 1.777...:1  -> 56.25% example: 1280x720px 
Film A:    37:20  -> 1.85:1      -> 54.05% example: 1140x616px 
Film B:    21:9   -> 2.4:1       -> 41.84% example: 1140x477px
*/
$prop-1-1:  100%;
$prop-4-3:  75%;
$prop-5-3:  61.8%;
$prop-16-9: 56.25%;
$prop-177:  54.05%;
$prop-239:  41.84%;

%square {aspect-ratio: 1/1;}
%portrait {aspect-ratio: 4/3;}
%divine {aspect-ratio: 5/3.09023486;}
%landscape {aspect-ratio: 1/1;}
%film-a {aspect-ratio: 1/1;}
%film-b {aspect-ratio: 1/1;}