Lineal measure has reference to length only.
Superficial measure (or the surface) includes length, and breadth.
Solid measure (or the content) comprehends length, breadth, and thickness.
MENSURATION OF PLANES.
The area of any plane figure is the superficial measure contained within its extremes, or bounds. This area is estimated by the number of small squares that may be contained in it, the side of these measuring squares being an inch, a foot, or any other fixed quantity, and hence the area is said to be so many square inches, square feet, &c. Vide Table, Square measure. [Page 275].
To find the area of a parallelogram, whether a square, rectangle, &c.
Multiply the length by the breadth, or perpendicular height, for the area required.
Example.—Required the area of a rectangle, whose length is 9 feet, and breadth 4 feet.
9 × 4 = 36 feet. The required area, or surface.