Quadrilaterals are four-sided polygons with four angles. The word "quadrilateral" comes from Latin words meaning "four sides."
All quadrilaterals have four sides, four vertices (corners), and interior angles that add up to 360 degrees.
Quadrilaterals are classified based on their side lengths, angle measures, and parallel sides.
Some quadrilaterals belong to multiple categories. For example, a square is also a rectangle and a rhombus.
A square is a quadrilateral with four equal sides and four right angles (90 degrees each).
A square is the most regular quadrilateral because it has both equal sides and equal angles.
A rectangle is a quadrilateral with four right angles and opposite sides that are equal and parallel.
Every square is a rectangle, but not every rectangle is a square. A rectangle only needs right angles and parallel opposite sides.
A rhombus is a quadrilateral with all four sides equal in length.
Every square is a rhombus, but not every rhombus is a square. A rhombus doesn't need to have right angles.
A parallelogram is a quadrilateral with both pairs of opposite sides parallel.
Rectangles, squares, and rhombuses are all special types of parallelograms with additional properties.
A trapezoid is a quadrilateral with at least one pair of parallel sides.
Some definitions say a trapezoid has exactly one pair of parallel sides, while others say at least one pair. In your class, follow your teacher's definition.
A kite is a quadrilateral with two distinct pairs of adjacent sides that are equal in length.
Kites look like the traditional flying kites. They have no parallel sides unless they are special cases like squares.
Many quadrilaterals are related to each other through shared properties.
When classifying quadrilaterals, start with the most specific category first. For example, call a shape with four equal sides and four right angles a "square" rather than just a "rectangle."