3. In 47 ares how many square meters?

4. In 60.25 hectares how many centares?

5. How many square meters in a building lot 8 m. by 32 m.? 6. How many building lots, each containing 225 sq. m., can be formed from a field containing 9 hectares?

7. How many hectares in a farm 1.024 Km. in width and 1.625 Km. in length?

8. What is the cost of a mirror 2.25 m. by 1.44 m., at $3.84 per sq. m.?

9. How many lots 25 m. wide by 60 m. deep, or having an equivalent area, can be laid out from 6 hectares?

10. A man bought a piece of land for $6950.50, and sold it for $7603.30, by which transaction he made $6.80 a hectare; how many hectares were there?

11. If the forward wheels of a carriage are 3.5 meters in circumference, and the hind weels 4.8 meters, how many more. times will the forward wheels revolve than the hind wheels, in running a distance of 8.4 kilometers?

CUBIC MEASURE.

230. The unit for measuring ordinary solids is the cubic meter.

TABLE.

1000 Cu. Millimeters, cu. mm. = 1 Cu. Centimeter = 1000 Cu. Centimeters, cu. cm. = 1 Cu. Decimeter 1000 Cu. Decimeters, cu. dm. = 1 CU. METER

.061 cu. in.

=

=

61.027 cu. in. (35.317 cu.ft. 1.308 cu. yd.

NOTES.-1. The cubic meter is used in measuring embankments, excavations, etc.; cubic centimeters and cubic millimeters for minute bodies.

2. Since units of cubic measure form a scale of thousands, each denomi. nation must have three places of figures.

231. The unit of Wood Measure is the ster, and is equal to a cubic meter, or 35.317 cubic feet.

8. In 5000 U. S. bushels, how many hectoliters? How many dekaliters?

9. In 875 cu. yd. how many cu. m. ?

10. In 1000 cu. m. how many cu. yd.?

11. Reduce 1728 gal. wine to liters; to dekaliters.

12. In 244 sq. m. how many sq. yd.? How many sq. ft.? 13. Reduce 220 oz. Av. to grams; to kilograms.

240. APPROXIMATE VALUES.

When no great accuracy is required, we may, for all practical purposes, consider

241. To reduce avoirdupois ounces to grams: Multiply by 30, and then deduct one-twentieth (5 per cent.). NOTE.-Answer too great by about 5g. for every 1000 g. of the result. 242. To reduce avoirdupois pounds to kilograms: Divide by 2, and then deduct one-tenth.

NOTE.-Answer too small by about 8 kilos for every 1000 kilos of the result. If, instead of, be deducted, the answer will be too great by 2 kilos for every 1000 kilos of the result.

243. To reduce avoirdupois pounds to half-kilograms, or German pounds:

Deduct one-tenth.

NOTE.-The answer by this rule will be too small by about 8 German pounds for every 1000 German pounds of the result. If be deducted, the answer will be too great by 2 German pounds for every 1000 German pounds of the result.

244. To reduce tons (2000 lbs.) to metric tons: Deduct one-tenth.

NOTE. The same relative error as in Art. 242.

245. To reduce yards to meters:

Deduct one-twelfth.

NOTE.-Answer too great by 21 m. for every 1000 m. of the result.

246. To reduce square yards to square meters:

Deduct one-sixth.

NOTE. Answer too small by about 3 sq. m. for every 1000 sq. m. of the result.

247. To reduce cubic yards to cubic meters:
Divide by 1.3.

NOTE.-Answer too great by about 6 cu. m. for every 1000 cu. m. of the

result.

248. To reduce U. S. gallons to liters:

Multiply by 4, and then subtract one-twentieth (5 per cent.).
NOTE.-Answer too great by about 47. for every 1000 7. of the result.

249. To reduce U. S. bushels to hectoliters: Divide by 3, and then add one-twentieth (5 per cent.). NOTE.-Answer too small by about 7hl. for every 1000 hl. of the result.

250. To reduce grams to avoirdupois ounces: Divide by 30, and then add one-twentieth (5 per cent.).

NOTE.-Answer too small by about 8 ounces for every 1000 ounces of the

result.

251. To reduce kilograms to avoirdupois pounds: Multiply by 2, and then add one-tenth.

NOTE.-Answer too small by about 2 lb. av. for every 1000 lb. av. of the

result.

252. To reduce German pounds, or half-kilograms, to avoirdupois pounds:

Add one-tenth.

NOTE.-Same error as in Art. 251.

253. To reduce metric tons to U. S. tons (2000 lbs.): Add one-tenth.

NOTE.-Answer too small by about 2 U. S. tons for every 1000 tons of the

result.

254. To reduce meters to yards:

Add one-twelfth, and 1% of the original number.

NOTE.-Answer will be too small by only yd. for every 1000 yd. of the

result.

This method is used at the New York Custom House and is sufficiently accurate for practical purposes.

If be added, the answer will be too small by about 2 yd. for every 1000 yd of the result. If be added, the answer will be too great by about 6 yd. for every 1000 yd. of the result.

Ex. According to above rule, how many yards in 324 meters?

255. To reduce square meters to square yards: Add one-fifth.

NOTE.-Answer too great by about 3 sq. yd. for every 1000 sq. yd. of the

result.

256. To reduce cubic meters to cubic yards: Multiply by 1.3.

NOTE.-Answer too small by about 6 cu. yd. for every 1000 cu. yd. of the

result.

257. To reduce liters to U. S. gallons:

Multiply by 2.11, and then divide by 8.

NOTE.-Answer too small by about 1.7 gal. for every 1000 gal. of the result.

Ex. In 144 liters, how many U. S. gallons?

OPERATION.

144

144

288 8) 303.84

37.98

(Exact result should be 38.04. Error only .06 gal.

258. To reduce hectoliters to U. S. bushels. Multiply by 3, and then subtract one-twentieth (5 per cent.). NOTE.-Answer too great by about 4 bu. for every 1000 bu. of the result.

259. FOREIGN WEIGHTS

Metric system used in the assess- 1 Pound (kilogram) = 1.102 lb. av.