Quadrilaterals have 4 sides and angle sum 360°. Each special type — parallelogram, rectangle, rhombus, square, trapezoid — has unique properties.
Opposite sides parallel and equal; opposite angles equal; diagonals bisect each other. Area = base × height.
Rectangle: parallelogram with 4 right angles; diagonals equal. Rhombus: parallelogram with 4 equal sides; diagonals perpendicular. Square: both rectangle AND rhombus.
Exactly one pair of parallel sides (bases). Area = ½(b₁+b₂)×h. Isosceles trapezoid: non-parallel sides equal; base angles equal.
For any polygon with n sides: sum of interior angles = (n−2)×180°. For a quadrilateral: (4−2)×180°=360°. Regular polygon: each interior angle = (n−2)×180°/n.
Q1: The sum of interior angles of a hexagon (6 sides) is:
Q2: A rhombus has 4 equal sides. Its diagonals are:
Q3: A trapezoid has bases 8 and 12 and height 5. Its area is: