The most popular aspect ratio is 4:3 (4 by 3). Early television and computer video formats are in a 4:3 aspect ratio, which means that the width of the image is 4/3 or (1.33) times the height. Examples: A 15 inch monitor is 12 inches wide by 9 inches high (9 x 4/3 = 12). A resolution of 640 x 480 is a 4:3 format (480 x 4/3 = 640). Other formats are 5:4 used by the 1280 x 1024 SXGA resolution, 16:9 is used by HDTV, and 3:2 for 35mm slides.