the.com/diameter
the only line bold enough to walk straight through the heart of a circle
means the length of a straight line passing through the center of a circle or sphere, connecting two points on its edge — twice the radius.
from From Greek 'diametros,' built from 'dia-' (through, across) and 'metron' (measure) — literally 'the measure across.' It traveled through Latin 'diametrus' and Old French before settling into English, but the bones are pure geometry: a Greek surveyor's instinct to ask not how big a circle is, but how far it is straight through. The same 'metron' echoes in 'meter,' 'thermometer,' and anything else that measures.
- exact value
- always twice the radius, no exceptions
- pi link
- circumference divided by it equals pi
- longest chord
- no chord beats it inside a circle
- symbol
- often written as a slashed-zero phi
- sphere too
- governs volume and surface area calculations
earth's equatorial diameter — 12,756 km across at the widest point
sun's diameter — 1.39 million km, 109 times wider than earth
great red spot diameter — jupiter's storm is roughly 16,000 km across