What is a Rectangle?
A quadrilateral with four right angles.
A rectangle is a flat, two-dimensional (2D) shape with:
- Four sides
- Four right angles (each angle measures 90°)
- Opposite sides that are equal in length and parallel
Fun fact: Squares are special types of rectangles because they also have four right angles, but in a square, all four sides are equal.
Rectangles are two-dimensional (flat) shapes, so we usually see them in drawings, on screens, or as the faces of three-dimensional objects, like the sides of a box, a door, or a book.
When Do Students Learn About Rectangles?
Students begin learning about rectangles in early grades while exploring basic shapes, and later study their properties in detail.
Grades K–2 – Recognizing Rectangles
Students learn to identify rectangles by their four sides and right angles while comparing them to other shapes.
Grades 3–5 – Understanding Rectangle Properties
Students learn to calculate area and perimeter and compare rectangles to squares and other quadrilaterals.
Grades 6+ – Applying Rectangles in Geometry
Students use rectangles in coordinate geometry, proofs, and real-world math problems involving measurement and scaling.
