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Mathematics · 术语表

什么是 Right angle?

Definition 18.1 Primary & Middle School Mathematics · 第 18 章 — Shapes and Right Angles

A right angle is the corner angle of a sheet of paper, or of the set square. Two lines making a right angle are perpendicular. In figures, a right angle is marked with a small square in the corner.

Only the first angle is right — and only the little square mark, or the set square, can certify it: eyes alone are easily fooled.
Only the first angle is right — and only the little square mark, or the set square, can certify it: eyes alone are easily fooled.
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