Some common aspect ratios

1.333:1 (4:3) Old television & computer monitor standard

1.41:1 Lichtenberg ratio 1:√2 ~1:1.4142, ISO 216paper sizes (A4)

1.5:1 (3:2) Classic 35 mm film

1.6:1 (8:5) (Credit cards are 85.6 × 54 mm which is ~1.59:1)

1.618:1 The golden ratio

1.667:1 (5:3) A common European widescreen standard

1.778:1 (16:9) HD video standard

1.85:1 A common US widescreen cinema standard

2.39:1 A current widescreen cinema standard