right angle
Học thuậtThân thiện
Definition
- Noun:
- A 90-degree angle: A right angle is an angle that measures exactly 90 degrees. It is the angle formed between two lines or surfaces that are perpendicular to each other.
Usage
- The term "right angle" is used in geometry, mathematics, engineering, architecture, and everyday contexts to describe a perfect quarter-turn or a square corner.
- It is often used with the preposition "at" (e.g., "meet at a right angle") or "of" (e.g., "an angle of 90 degrees is a right angle").
Examples
- Noun:
- The corner of a standard piece of paper forms a right angle.
- The two streets intersect at a right angle.
- A square has four interior right angles.
Advanced Usage
- "At right angles (to)": Perpendicular.
- The two panels were fixed at right angles to each other to form a sturdy frame.
- Conceptual Use: Can be used metaphorically to describe things that are fundamentally different or opposed.
- Their approaches to the problem were at right angles; one was creative while the other was strictly analytical.
Variants and Related Words
- Right-angled (adj): Having or forming a right angle.
- A right-angled triangle has one 90-degree angle.
- Perpendicular (adj/noun): At an angle of 90° to a given line, plane, or surface. This is a key synonym describing the relationship that creates a right angle.
- Orthogonal (adj): A formal term, especially in mathematics, meaning involving right angles or perpendicularity.
Synonyms
- 90-degree angle: The direct descriptive synonym.
- Quarter-turn: Describes the rotational equivalent.
Related Phrases
- Make a right angle: To form or create a 90-degree angle.
- Fold the paper carefully to make a right angle.
- Form a right angle: To come together at 90 degrees.
- The two walls form a right angle at the corner of the room.
Related Idioms
- While not a common idiom itself, the concept is embedded in phrases like "by the square" (archaic) meaning done precisely or correctly, alluding to the right angle of a carpenter's square.
Noun
- the 90 degree angle between two perpendicular lines