直径(ちょっけい)

直径(ちょっけい) is the diameter - a line passing through the center of a circle connecting two points on the edge.

KANJI BREAKDOWN:

• 直(ちょく): straight, direct
• 径(けい): path, diameter

MATHEMATICAL RELATIONSHIPS:

• 直径(ちょっけい) = 半径(はんけい) × 2 (diameter = radius × 2)
• 円周(えんしゅう) = 直径(ちょっけい) × π (circumference = diameter × π)
• 面積(めんせき) = π × (半径(はんけい))² (area formula)

COMMON EXPRESSIONS:

• 直径(ちょっけい)〜センチ: ~ cm in diameter
• 直径(ちょっけい)を測(はか)る: to measure the diameter

RELATED GEOMETRY TERMS:

• 半径(はんけい): radius
• 円周(えんしゅう): circumference
• 円(えん): circle
• 球(きゅう): sphere