Translation guide
A polygon is a flat shape with straight sides. In Japanese, the most common word is 多角形 (たかくけい), used in geometry and everyday contexts. For specific polygons, Japanese uses number + 角形 (かくけい) or 角形 (かっけい), e.g., 三角形 (さんかくけい) for triangle. In computing and graphics, ポリゴン (porigon) is the standard loanword.
Referring to any flat shape with straight sides, in math or everyday description.
The standard term for polygon in geometry and general use. Safe for all contexts.
この多角形の面積を計算してください。
Please calculate the area of this polygon.
Loanword used mainly in computer graphics, 3D modeling, and gaming. Not typically used in math class.
この3Dモデルは多くのポリゴンで構成されています。
This 3D model is made up of many polygons.
Naming a triangle, quadrilateral, pentagon, etc.
Attach the number (in Japanese reading) to 角形. For 3 and 4, 三角形 (さんかくけい) and 四角形 (しかくけい) are most common. For higher numbers, use the on'yomi number + 角形 (かくけい) or 角形 (かっけい). 五角形 (ごかくけい) and 五角形 (ごかっけい) both exist, but 五角形 (ごかくけい) is more standard.
三角形の内角の和は180度です。
The sum of the interior angles of a triangle is 180 degrees.
この図形は六角形です。
This shape is a hexagon.
A polygon with all sides and angles equal.
Prefix 正 (せい) means 'regular'. Use with general 多角形 or specific shapes: 正三角形 (せいさんかくけい) equilateral triangle, 正五角形 (せいごかくけい) regular pentagon.
正多角形はすべての辺と角が等しい。
A regular polygon has all sides and angles equal.
多角形 is the native Japanese term used in mathematics and formal contexts. ポリゴン is a loanword from English, used almost exclusively in computing, 3D graphics, and gaming. Using ポリゴン in a geometry class would sound odd.
数学の授業で多角形について学んだ。
We learned about polygons in math class.
このゲームのキャラクターは低ポリゴンで描かれている。
The characters in this game are rendered with low polygons.