A = area, a = length of side, b = length of side joined to a side of length a, h = perpendicular height, A = an interior angle
Comments
A parallelogram is a four-sided shape with two pairs of parallel sides that are not at right angles. The area of a parallelogram is equal to the base times the perpendicular height taken from that base, or the product of the lengths of two adjacent sides and the sine of an interior angle.
References
CRC Standard Mathematical Tables , 26th edition, CRC, 1981