196. This table is used in measuring distances and lines. The yard is the primary unit. SURVEYORS' MEASURE. 197. Used in measuring land. The unit is a Gunter's chain which is equal to 66 feet. It is divided into 100 equal parts called links. MEASURES OF SURFACE. DEFINITIONS. 198. A Surface is a magnitude that has length and breadth, without thickness. 199. An Angle is the opening between two lines that meet at a point; as, BAC. The lines AB and AC are called sides, and the point A is called the vertex of the angle. If the angle BAD is equal to the angle BAC, BA is perpendicular to A B ANGLE. Fig. 2. B D A DC, and the angles BAD and BAC RIGHT ANGLES. Fig. 1. are right angles. 200. A Square is a plane figure bounded by four equal sides, and whose angles are right angles; as Fig. 3. 201. A Rectangle is a plane figure whose opposite sides are equal, and whose angles are right L angles. A square foot is a square K whose sides are each equal to one foot; a square yard is a square whose sides are each equal to 1 yard. A B SQUARE. Fig. 3. A B C D M P The unit of measure of a surface is a square, one of whose sides is equal to the unit of length. 202. The Area of a surface is an expression for that surface in terms of a square unit. Figure 4 represents a square yard, each side of which is three feet long; the area is nine square feet. The area of a square or rectangle is found by multiplying its length by its breadth. SQUARE MEASURE. Used for measuring surfaces. TABLE. 144 square inches (sq. in.) make 1 square foot 9 square feet 66 1 square yard. sq. ft. sq.ft. sq. yd. This is used in finding the area of land. TABLE. 10,000 square links (sq. li.) make 1 square chain. sq. ch. 10 square chains A. 66 1 acre 66 1 square mile sq. mi. 640 acres In government surveys, a square mile is called a section, and 36 sections make a township. MEASURE OF VOLUME AND CAPACITY. 203. A volume or solid is a magnitude that has length, breadth, and thickness or height. 204. A cube is a volume or solid bounded by six equal squares. The bounding squares are called faces. The sides of the squares are called edges of the cube. 205. A unit of volume is a cube whose edges are equal to a CUBE. unit of length. CUBIC MEASURE. PARALLELOPIPEDON. 206. This is used in measuring volumes or solids. TABLE. 1728 cubic inches (cu. in.) make 1 cubic foot 27 cubic feet 16 cubic feet (cu. ft.) make 1 cord foot DRY MEASURE. 207. This is used in measuring grain, fruit, salt, etc. |