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Identify rectangles

A rectangle is a closed two-dimensional shape with four straight sides and four right angles; its opposite sides are equal in length. Identification includes rectangles in different sizes and orientations, including squares, and distinguishes them from shapes that merely appear rectangular or have four sides without four right angles. This understanding supports classifying shapes and reasoning about area and perimeter.

Detailed Explanation: Identify rectangles

A rectangle is a closed shape with:

  1. Four straight sides
  2. Four square corners, called right angles
  3. Opposite sides the same length

A rectangle can be turned or tilted. It does not have to stand straight up. A square is also a rectangle because it has four straight sides and four right angles.

Example

Imagine a tilted shape with side lengths:

  • Top side: 66 units
  • Right side: 33 units
  • Bottom side: 66 units
  • Left side: 33 units

Check the shape:

  • It is closed.
  • It has four straight sides.
  • Each corner is a right angle.
  • Opposite sides are equal: (6=6)(6=6) and (3=3)(3=3).

Therefore, the shape is a rectangle.

Do not decide only by how a shape looks. A four-sided shape is not a rectangle if one of its corners is not a right angle.

Learn by doing: Identify rectangles

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Identify Shapes 2D - Count Rectangles (Real World)


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