外角 (wài jiǎ) — (geometry) exterior angle

Definition

noun

(geometry) exterior angle

Measure word · 个

外角外角。
Sān wài jiǎ xíng de wài jiǎ děng yú bù xiāng lín de liǎng gè nèi jiǎo zhī hé.
The exterior angle of a triangle equals the sum of the two non-adjacent interior angles.
外角外角。
Zhè dào tí yāo qiú nǐ jì suàn zhè ge duō biān wài jiǎ xíng de suǒ yǒu wài jiǎ.
This problem requires you to calculate all the exterior angles of this polygon.
外角外角72。
Zhèng wǔ biān wài jiǎ xíng de měi gè wài jiǎ shì 72 dù.
Each exterior angle of a regular pentagon is 72 degrees.

Compound word

构词法gòucífǎ

偏正piānzhèngModifier + head

The first part narrows down the second: it says what kind of thing the head is.

外 marks the outside, and 角 is an angle, so the term names an angle lying outside.

Characters in this word

Most characters — around four in five — are built this way: one part hints at the meaning, the other at the pronunciation.

Meaning part形符xíngfú

Sound part声符shēngfú

月

The sound has drifted apartThe sound part was a clue two thousand years ago — it often still helps, but not always.

外 pairs 卜 with 月, a crescent moon; in its older form, the 卜 part had a horizontal bar extending outward, giving the sense of outside.

A drawing of the thing itself, worn down over three thousand years into a few strokes.

The form 角 is a picture of a horn.