The following rules will be found of service in many cases that may arise in land parceling, particularly in the computation of areas.

To find the area of a four-sided tract, whose sides are perpendicular to each other (called rectangle): Multiply the length by the breadth, and the product will be the area.

To find the area of a four-sided tract, whose opposite sides are parallel, but whose angles are not necessarily right angles (called a parallelogram): Multiply the base by the perpendicular height, and the product will be the area.

To find the area of a three-sided tract (called a triangle): Multiply the base by half of the perpendicular height, and the product will be the area.

To find the area of a four-sided tract, having two of its sides parallel (called a trapezoid): Multiply half the sum of the two parallel sides by the perpendicular distance between these sides, and the product will be the area.

To ascertain the contents of a tract, bounded by four straight lines, of which no two are parallel to each other (called a trapezium), and the length of each line is ascertained, and the two opposite angles are supplements of each other): Add all the four sides together, and halve their sum; subtract separately each side from that sum; and the four remainders thus obtained multiply continually together, and extract the square root of the last product. The result will be the contents or area of the tract. OR, divide the tract by lines into triangles and trapezoids, and ascertain and add together their several areas, - the sum of which will be the area of the tract proposed.

Land bounded by an irregular line - as a stream of water, or a winding road - is measured as follows, viz.: Draw a base line as near as practicable to the actual line of the road or stream; and at different places in the base line, equidistant from each other, take the distance to the line of the stream or road. Add the sum of all the intermediate lines (or breadths) to half the sum of the first breadth and last breadth, and multiply the sum thus obtained by the common distance between the breadths. The result will be the area of the land in question.

Should the breadths be measured at unequal distances on the base line, add all the breadths together, and divide their amount by the number of breadths for the mean breadth, and multiply the quotient so obtained by the length of the base line.