This document discusses properties and formulas for calculating the areas of parallelograms, rhombuses, and trapezoids. It states that the area of a parallelogram is equal to its base times its height, and that opposite sides of a parallelogram are equal and parallel. The area of a rhombus is half the product of its diagonals. Finally, the area of a trapezoid is half the product of the sum of the parallel sides and the distance between them.