平行四辺形(へいこうしへんけい)

Composed of 平行(へいこう) (parallel) + 四辺形(しへんけい) (quadrilateral, four-sided figure). Literally "parallel quadrilateral." The standard term used throughout Japanese elementary, middle, and high school mathematics.

KEY PROPERTIES (the way they are stated in Japanese math classes):

• 向(む)かい合(あ)う辺(へん)は平行(へいこう)で長(なが)さが等(ひと)しい: opposite sides are parallel and equal in length
• 向(む)かい合(あ)う角(かく)の大(おお)きさは等(ひと)しい: opposite angles are equal
• 対角線(たいかくせん)はそれぞれの中点(ちゅうてん)で交(まじ)わる: the diagonals bisect each other
• 面積(めんせき) = 底辺(ていへん) × 高(たか)さ: area = base × height

Common collocations

• 平行四辺形(へいこうしへんけい)の面積(めんせき): the area of a parallelogram
• 平行四辺形(へいこうしへんけい)の性質(せいしつ): properties of a parallelogram
• 平行四辺形(へいこうしへんけい)を描(か)く: to draw a parallelogram
• 平行四辺形(へいこうしへんけい)になる条件(じょうけん): the conditions for (a shape) to be a parallelogram

Related geometry terms

• 長方形(ちょうほうけい): rectangle — a parallelogram with all right angles
• 正方形(せいほうけい): square — a rectangle with all sides equal
• ひし形(がた): rhombus, diamond — a parallelogram with all sides equal
• 台形(だいけい): trapezoid / trapezium — a quadrilateral with only one pair of parallel sides
• 四角形(しかくけい): quadrilateral — the general term for any four-sided figure
• 多角形(たかくけい): polygon
• 平行(へいこう): parallel
• 対角線(たいかくせん): diagonal (line)
• 底辺(ていへん): base (of a triangle or parallelogram)
• 高(たか)さ: height

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Neutral and technical. A standard math-class word; used mostly in educational, mathematical, and technical-drawing contexts.