subtend

/səb'tend/
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Thân thiện
subtend

The angle subtends the arc of the circle.

Definition
  1. Verb:
    • In geometry, to be opposite to: Specifically, to have a side or arc directly facing a particular angle or point. This is a precise mathematical relationship describing the position of one geometric element relative to another.
Usage

The verb subtend is used almost exclusively in technical, mathematical, and botanical contexts. It describes a spatial relationship where one line, side, or arc is positioned directly opposite a specified angle or point. - In geometry, a side of a triangle subtends the angle opposite to it. - In botany, a leaf or bract subtends the flower or branch that arises from its axil (the angle between the leaf and the stem).

Examples
  • Geometry:
    • In triangle ABC, side BC subtends angle A.
    • The chord subtends an arc of 60 degrees on the circle.
  • Botany:
    • A small leaf subtends each flower on the stalk.
    • The bracts that subtend the inflorescence are often brightly colored.
Advanced Usage
  • "to subtend an angle": This is the most common construction, meaning to be the side or line directly opposite and defining that angle.
    • The radius of a circle subtends a right angle at any point on the circumference.
  • "to subtend an arc": Used when a chord or line segment has its endpoints on the arc.
    • A diameter subtends a semicircular arc.
Variants and Related Words
  • Subtended (adj): Describing the element that is opposite. Often used in past participle form.
    • The subtended angle is 45 degrees.
  • Subtension (n): The state or relation of subtending. (This is a rare, technical noun form).
Synonyms
  • Be opposite to: The most direct synonym in a geometric sense.
  • Face: A less technical but sometimes used alternative (e.g., "The side facing the angle...").
Notes on Meaning

While the core meaning is consistent ("to be opposite to"), the application differs by field: 1. Mathematical Geometry: Describes the relationship between angles and sides in polygons, or arcs and chords/lines in circles. 2. Botany: Describes the relationship where a leaf-like structure sits at the base of, and is directly adjacent to, another plant part like a flower or branch.

subtend

The angle subtends the arc of the circle.

Verb
  1. be opposite to; of angles and sides, in geometry

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