trigonometry
trigonometry — noun
1. a branch of mathematics that studies how the angles and side lengths of triangle
a branch of mathematics that studies how the angles and side lengths of triangles are connected, often used to calculate distances or heights that are difficult to measure directly
Sumin found trigonometry difficult at first but improved after practising the formulas every day.
personal experience + practice collocation
The surveyor used trigonometry to estimate the height of the bridge across the river.
used + noun to [verb] — purpose structure
In trigonometry class, students learn how to find unknown angles using sine and cosine.
Without trigonometry, engineers could not design curved bridges or safe highway ramps.
Hassan drew a right-angled triangle to show how trigonometry connects the sides to the angles.
用法筆記
Commonly used as an uncountable noun; you study trigonometry as a subject, not 'a trigonometry'. Frequently abbreviated informally to trig in spoken English (e.g., 'I have a trig test tomorrow').