Vocabulary (Basic Geometry)

English terms related to Basic Geometry:

The basics

• Point.
• Line.
• Ray.
• Line segment.

Lines

• Parallel lines.
• Intersecting lines.
• Perpendicular lines.

Angles

• Vertex.
• Sides.
• Acute angle.
• Right angle.
• Obtuse angle.
• Stright angle.
• Reflex angle.
• Complementary angles.
• Suplementary angles.
• Degree.
• Opposite angles.
• Congruent angles.

Circle and circumference

• Centre.
• Radius.
• Diametre.
• Arc.
• Chord.
• Central angle.
• Inscribed angle.
• Tangent line.
• Intersecting line.
• No intersection line or outside line.

Special lines

• Perpendicular bisector.
• Angle bisector.

Geometric shapes

• Polygon: triangle, quadrilateral, pentagon, hexagon, heptagon, octogon, nonagon, decagon...
• Regular polygon.
• Vertices and sides.

Triangles

• Types of triangles by angles:
  • Acute triangle.
  • Right triangle.
  • Obtuse triangle.
• Types of triangles by sides:
  • Equilateral triangle.
  • Isosceles triangle.
  • Scalene triangle.

Quadrilaterals

• Square.
• Rectangle.
• Parallelogram.
• Rhombus.
• Kite.
• Trapezium.

Symmetry

• Symmetric shapes.
• Axis of symmetry.