Definition

1. Noun:
   • The branch of geometry that deals with two-dimensional figures and their properties: "Plane geometry" is the study of shapes, lines, points, and angles that exist on a flat, two-dimensional surface, or plane. It involves concepts such as triangles, circles, polygons, and parallel lines.

Examples of Usage

• Noun:
  • In high school, students often study plane geometry before moving on to solid geometry.
  • The theorem is a fundamental concept in plane geometry.
  • Calculating the area of a circle is a classic problem in plane geometry.

Advanced Usage

• "Problems in plane geometry": This phrase refers to specific mathematical exercises or puzzles involving two-dimensional shapes.
  • The math competition featured several challenging problems in plane geometry.

Variants and Related Words

• Geometry (n): The broader branch of mathematics concerned with the properties and relations of points, lines, surfaces, and solids.
  • Geometry is divided into subfields like plane geometry and solid geometry.
• Solid geometry (n): The branch of geometry that deals with three-dimensional figures.
  • After mastering plane geometry, the class progressed to solid geometry.

Synonyms

• Euclidean geometry (in its two-dimensional aspect): The system of geometry based on the axioms of Euclid, typically first studied in its planar form.
• Two-dimensional geometry: A descriptive synonym emphasizing the dimension of the figures studied.

Related Phrases

• Plane figure (n): A two-dimensional geometric shape studied in plane geometry.
  • A square is a common plane figure.

Noun

1. the geometry of 2-dimensional figures