Classifying Quadrilaterals
Classifying quadrilaterals organizes four-sided polygons by their properties into a hierarchy. In Grade 6 Saxon Math Course 1, students distinguish parallelograms (two pairs of parallel sides), trapezoids (exactly one pair), rectangles (parallelogram with four right angles), rhombuses (parallelogram with four equal sides), and squares (rectangle and rhombus). Every square is a rectangle, every rectangle is a parallelogram, and every parallelogram is a quadrilateral, forming a nested classification system.
Key Concepts
New Concept Quadrilaterals are four sided polygons that can be sorted, or classified, by the characteristics of their sides and angles.
A quadrilateral is a polygon with four sides. What’s next This is the foundation for identifying shapes. Next, you'll use these definitions to analyze relationships between quadrilaterals in worked examples and practice problems.
Common Questions
What is a quadrilateral?
Any polygon with exactly four sides and four vertices.
What makes a rectangle different from a general parallelogram?
A rectangle is a parallelogram with four right angles (90°).
What makes a rhombus different from a general parallelogram?
A rhombus is a parallelogram with all four sides equal in length.
Is a square a rectangle?
Yes. A square has four right angles (making it a rectangle) and four equal sides (making it a rhombus), so it is both.
What is the difference between a trapezoid and a parallelogram?
A trapezoid has exactly one pair of parallel sides; a parallelogram has two pairs.