Football: why the ball has 20 hexagons and 12 pentagons.

The World Cup starts in an hour or so — and how can we miss a math story about football? Let's check out story #53.

Have you ever kicked a football? Ever noticed the pentagons and hexagons on it, and wondered why they're there? Math doesn't leave us alone, does it?

Historically, footballs were built from a combination of hexagonal and pentagonal panels because they fit together like a puzzle to make an almost perfectly spherical shape. The classic design has 32 panels — 20 hexagons and 12 pentagons — stitched closely together from leather or synthetic plastic. It holds its shape when kicked, improves aerodynamics and close control, and the traditional black-and-white scheme also helps television audiences keep track of the ball.

Why 32 panels?

A ball with optimum roundness delivers the most reliable aerodynamics: straight flight and a controlled bounce. The 32-panel construction ensures the ball can travel through the air for longer before meeting significant resistance. In simpler terms, a 32-panel ball is better at holding a high, steady speed for longer, which gives the reliable flight that players value.

Modern footballs, on the other hand, are thermally bonded rather than stitched. The way the panels are joined is what distinguishes them from their stitched equivalents — and the process needs a lot less labour than sewing.