Quadrilaterals
Quadrilaterals - polygons with 4 sides
Parallelograms - quadrilaterals with opposite sides parallel

Area = BH (base x height)
ex; b = 6, h = 4
6 × 4
Area = 24
Opposite angles are equal
Adjacent angles (angles next to each other) always sum to 180°
Opposite sides have equal lengths
Rectangle - all angles equal to 90°
Rhombus - all side lengths are equal
Trapezoids - quadrilaterals with one pair of opposite sides parallel

Area = (B1 + B2 / 2) x H
B = base, H = height
ex; b1 = 8, b2 = 10, h = 6
(8 + 10 / 2) x 6
9 × 6
Area = 54