A4 sheet vs Adult hand: size comparison
A4 sheet: 29.7 cm. Adult hand: 18.9 cm. Both silhouettes are drawn at the same scale.
Size ratio: ×1.6
A4 sheet
29.7 cm
What is measured Height of an A4 sheet (ISO 216)
Fold an A4 in half and you get A5: the side ratio stays √2.
Source : Wikipedia — ISO 216
Adult hand
18.9 cm
What is measured Length of an adult hand, wrist to middle fingertip
A hand has 27 bones: both hands hold a quarter of all the bones in the body.
Source : Wikipedia — Hand