Two-Dimensional Shapes

Definition

• Two-dimensional (2D) shapes are flat.
• They are called two-dimensional because they have two dimensions: length and width.

Features of Shapes

• Shapes have features that help identify their type:
  • Sides: Straight lines that make up the shape.
  • Corners: Where two sides meet; also called vertices.

Quadrilaterals

• A family of shapes with four sides and four corners.
• The prefix "quad" means four.
• Each quadrilateral has unique characteristics.

Types of Quadrilaterals

1. Square
   • Four sides of equal length.
   • All sides are parallel.
2. Rectangle
   • Four sides with two pairs of equal length.
   • Opposite sides are parallel.
3. Rhombus (or Diamond)
   • Four sides of equal length.
   • Opposite sides are parallel.
   • Looks like a leaning square.
4. Kite
   • Four sides with two pairs of equal length.
   • No parallel sides.
   • Different from a rhombus in that not all sides are the same length (two pairs).

Other Shapes

1. Triangle
   • Three sides and three corners.
   • The prefix "tri" means three.
2. Circle
   • Round shape formed by a curved line.
   • All points on the line are equidistant from the center.
   • No sides or corners.

Conclusion

• There are many different types of two-dimensional shapes.
• Encouragement to find these shapes in the classroom.