Geometry is the branch of mathematics concerned with the properties and relations of points, lines, surfaces, and solids. Below are important geometry terms, their definitions, and English translations.
Basic Terms and Definitions
- Polygon: A closed plane figure with three or more straight sides.
- Vertex: A point where two or more lines, edges, or sides meet; the corner of a shape.
- Equilateral Triangle: A triangle with all three sides of equal length and all angles equal (each 60ยฐ).
- Isosceles Triangle: A triangle with two sides of equal length and two equal angles.
- Scalene Triangle: A triangle with all sides and angles of different lengths and measures.
- Congruent: Figures or objects that are identical in shape and size.
- Corresponding Side: Sides that occupy the same relative position in different shapes.
- Similar Figures: Figures that have the same shape but not necessarily the same size; their corresponding angles are equal and sides are proportional.
- Proportional: Having a constant ratio between corresponding sides or quantities.
- Quadrilateral: A polygon with four sides and four angles.
- Parallelogram: A quadrilateral with opposite sides parallel and equal in length.
- Rhombus: A parallelogram with all sides of equal length.
- Rectangle: A parallelogram with four right angles.
- Square: A rectangle with all sides equal in length.
- Trapezoid (US) / Trapezium (UK): A quadrilateral with at least one pair of parallel sides.
- Parallel: Lines or sides that are always the same distance apart and never meet.
- Axis of Symmetry: A line that divides a figure into two mirror-image halves.
- Diagonal: A line segment connecting non-adjacent vertices of a polygon.
- Pentagon: A polygon with five sides and five angles.
- Hexagon: A polygon with six sides and six angles.
- Heptagon: A polygon with seven sides and seven angles.
- Octagon: A polygon with eight sides and eight angles.
- Nonagon: A polygon with nine sides and nine angles.
- Decagon: A polygon with ten sides and ten angles.
- Circle: A set of all points in a plane that are a fixed distance from a center point.
- Radius: The distance from the center of a circle to any point on its circumference.
- Diameter: A straight line passing through the center of a circle, connecting two points on the circumference; twice the radius.
- Circumference: The perimeter or boundary line of a circle.
- Area: The measure of the surface enclosed by a shape.
- Perimeter: The total length of the sides of a polygon.
Other Terms
- Tetrapods: Animals with four limbs; not a geometry term, but related to biology.
- In Theory: Refers to something that is possible according to principles or ideas.
- Unlimited: Without any limits or boundaries.
Comments