The ratio of the height to the width of an image or video. There are typically square, wide, and vertical aspect ratios to fit your desired screen size. For example, images with vertical aspect ratios work best with Instagram stories, wide are good for YouTube videos, and square are most common.

The aspect ratio of a duct can be evaluated as the ratio of width to height. As the aspect ratio increases, vibration noise, friction and cost also increases.

That is a 16:9 aspect ratio.

the correct aspect ratio for 4x3 = 1.333 the correct aspect ratio for 16x9 = 1.777

The aspect ratio is the tires profile. For instance, a tire with a 60 aspect ratio means that the tires hight from tread to rim is 60% of the tires nominal width. The lower the aspect ratio # the wider the tire.