Howdy!
This box has a 4:3 aspect ratio. Its width is 80% of the page width. Its height is three quarters of its width.
3:2
width: 50%
height: two thirds of width
16:9
width: 50%
height: nine sixteenths of width
This box has a 4:3 aspect ratio. Its width is 80% of the page width. Its height is three quarters of its width.