Understanding 半径 (はんけい)
The word 半径 means "radius," the distance from the center of a circle to its edge. It is commonly used in geometry, measurements, and spatial descriptions.
Usage in Sentences
半径 is often used with numbers and units (e.g., センチメートル, キロメートル) to specify the size or range of circular areas. It can describe physical objects like circles or abstract ranges such as areas around a point.
Common Collocations and Patterns
- 半径＋数字＋単位 (e.g., 半径5センチメートル): specifying the radius length.
- 半径の範囲 (radius range): describing an area within a certain radius.
- 半径を測る (measure the radius): used when calculating or measuring.
Register and Usage Notes
半径 is a neutral, technical term used in both everyday and academic contexts. It is not casual slang but is common in school, work, and daily life when discussing measurements.
Common Learner Mistake
Avoid confusing 半径 (radius) with 直径 (diameter). 半径 is half the length of 直径. Remember 半径 is from center to edge, not across the whole circle.