平へい面めん図ず形けい

noun

plane figure

A geometric figure that lies entirely in a single plane, such as a triangle, square, or circle. Used in mathematics contexts.

• 平へい面めん図ず形けいの面めん積せきを求もとめる問もん題だいを解といた。

  I solved a problem to find the area of a plane figure.

• 三さん角かく形けいや四し角かく形けいは基き本ほん的てきな平へい面めん図ず形けいです。

  Triangles and quadrilaterals are basic plane figures.