2D Shapes

Two-dimensional (2D) shapes are flat figures that have length and width

There are several common 2D shapes, including polygons and circles. Polygons are closed 2D shapes with n straight sides. Some examples of polygons include:

  • Triangles (3 sides)
  • Quadrilaterals (4 sides)
  • Pentagons (5 sides)
  • Hexagons (6 sides)
  • Octagons (8 sides)

Polygons can be regular (all sides and angles equal), or irregular (varying side lengths and angles). Squares are regular quadrilaterals.

Triangles

Triangles have three sides and three angles and can be classified as:

  • Equilateral – all sides equal and all angles equal to 60°
  • Isosceles – two sides equal and base angles equal
  • Scalene – no sides equal
  • Right-angled – one angle equal to 90°
  • Obtuse – one angle greater than 90°
  • Acute – all angles less than 90°

Quadrilaterals

Quadrilaterals have four sides and four angles. Some examples include:

  • Squares (all sides equal and all angles equal to 90°), so it is a regular quadrilateral
  • Rectangles (opposite sides equal, all angles equal to 90°)
  • Parallelograms (opposite sides parallel and equal, opposite angles equal)
  • Rhombuses (all sides equal, opposite angles equal)
  • Trapezoids (one pair of opposite sides parallel)
  • Kites (two pairs of adjacent sides equal)

Circles

Circles are round 2D shapes with no corners or edges, just one curved line that is at a fixed distance from a central point.

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