Quadrilateral: A polygon with exactly 4 sides and 4 vertices (corners).
Side: One of the four straight lines that make up a quadrilateral.
Vertex (plural: vertices): A corner where two sides meet.
Angle: The space between two connected sides, measured in degrees.
Right angle: An angle that measures exactly 90° (like the corner of a square).
Parallel lines: Lines that never meet, always stay the same distance apart.
• Every quadrilateral has exactly 4 sides
• Every quadrilateral has exactly 4 vertices
• The sum of all interior angles equals 360°
• Sides can be equal or different in length
• Angles can be right angles (90°) or other measurements
Step 1: Count the sides (must be 4 to be a quadrilateral)
Step 2: Measure or compare side lengths
Step 3: Check for right angles (90°) or equal angles
Step 4: Look for parallel sides
Step 5: Compare with specific quadrilateral definitions
• Square: "Perfect" - all sides equal AND all angles 90°
• Rectangle: "Right" angles - all 90°, opposite sides equal
• Rhombus: "Diamond" shape - all sides equal, angles not 90°
• Parallelogram: "Parallel" - opposite sides parallel and equal
• Trapezoid: "Trap" - one pair of parallel sides only
• Kite: "Flying" kite shape - two pairs of adjacent equal sides
All angles 90°
A square has 4 equal sides and 4 right angles (90°).
All angles 90°
A rectangle has opposite sides equal and 4 right angles (90°).
Opposite angles equal
A rhombus has 4 equal sides, but angles are not necessarily 90°.
Other sides not parallel
A trapezoid has exactly one pair of parallel sides.
Opposite sides parallel
A parallelogram has opposite sides equal and parallel.
Perpendicular diagonals
A kite has two pairs of adjacent sides that are equal in length.