Unit 2 Classifying 2D shapes: quadrilaterals. A quadrilateral is a shape with four sides. Quad means four. Quadrilaterals can be classified according to the lengths of their sides, the number of parallel and perpendicular sides, and the size of their angles.

This document, "Unit 2 Classifying 2D shapes: quadrilaterals," explains that quadrilaterals are four-sided shapes whose interior angles sum to $360^\circ$. It illustrates this by showing how a quadrilateral can be divided into two triangles, each with angles summing to $180^\circ$.

The document then provides a table detailing six types of quadrilaterals with their defining properties:

• Square: All sides are equal, all angles are $90^\circ$.
• Rectangle: Opposite sides are equal, all angles are $90^\circ$.
• Rhombus: All sides are equal, opposite angles are equal.
• Parallelogram: Opposite sides are equal and parallel, opposite angles are equal.
• Trapezium: One pair of opposite sides is parallel.
• Kite: Two pairs of equal sides, one pair of equal angles.