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EXAMPLES.

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S. d.grs.

RULE. Multiply the principal, in cents, by the number of days, and point off five figures to the right hand of the product, which will give the interest for the given time, in shillings and decimals of a shilling, very nearly.

A note for 65 dollars, 31 cents, has been on interest 25 days; how much is the interest thereof, in New-England currency?

S cis.

Ans. 65,51=6551 X25==1,63975 ID REMARKE.- In the above, and likewise in the preceding practical Rules, (page 197) the interest is contined at six per cent. which admits of a variety of short methods of casting ; and when the rate of interest is 7 per cent. as established in New-York, &c. you may first cast the interest at 6 per cent and add thereto one sixti of itself, and the sum will be the interest at 7 per cent. wlich perhaps, many times, will be found more convenient than the general rule of casting interest.

Required the interest of 751. fer 5 months at 7 per ceut.

7,5 for 1 month.

5
som £. s. d.
37,5=1 17 6 for 5 months at 6 per cent.
+

6 3

EXAMPLE.

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Ans £2 3 9 for ditto at 7 per cent.

A SHORT METHOD FOR FINDING THE REBATE OF AN GIVEN SUM, FOR MONTHS AND DAYS.

RULE. Dminish the interest of the given sunn for the time by its own interest, and this gives the Rebate very

nearly. EXAMPLES. 1. What is the relate of 50 dollars for six months, it Snorren:..

S cts. The interest of 50 dollars for a months, is 1 50 And, the interest of I dol. 50 cts. for 6 months, is

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ins. Rehate, 46 9. What is the rebate of 150!. for 7 months, at 5 per cent.

£,. s. .

Interest of 1501. for 7 months, is
Interest of 41. 7s. Gu. for?montiis, is

2 61

Ans. £4 4 11} nearly. By the above. Rule, those who use interest tables in their counting houses, have only to deduct the interest of the interest, and the remainder is the discount.

A concise Rule to reduce the currencies of the different

States, where a dollar is an even number of shillings, to Federal Honey.

RULE I. Bring the given sum into a decimal expression by in spection, (as in Problem I. page 87) then divide the whole by ,s in New England and by ,4 in New-York currency, and the quotient will be dollars, cents, &c.

1. Reluce 541. Es. 3.d. New-England currency, to Federal Money.

,S)54,415 decimally expressed.

EXAMPLES.

Ans. 6181,38 cts. 2. Reduce 7s. 11jd. New England currency, to Federal Money. s. 1131.={0,399 then, ,3),399

Ans. $1,33 3. Resluce 5151. 16s. 10d. New-York, &c. currency to Federal Money.

„4)519,842 decimal

Ans: 81284,60%

4. Reduce 19s. 530. New-York, &c. currency, to Fede.

ral money.

,4)0,974 decimal of 19s. 5 d.

82,43) Ans. 5. Reduce 641. New-England currency, to Federal Money.

„5)64000 decimal expression.

8215,353 Ans. NOTE.—By the foregoing rule you may carry on the decimal to any degree of exactness; but in ordinary practice, the following Contraction may be useful.

RULE II. To the shillings contained in the given sum, annos o times the given pence, increasing the product by 2; then divide the whole by the number of shillings contained in a dollar, and the quotient will be cents.

EXAMPLES.

1. Reduce 45s.6d. New-England currency, to Feder ral Money.

6x8+2 50 to be annexed. 6)45,50 or 6)4550

$ cts. $7,582 Ans.

758 cents. =7,58. 2. Reduce 21. 10s. Id. New-York, &c. currency, t Federal Money.

9XS-+2=74 to be annexed. Then 8)5074

Or thus, 8)50,74

$ cis. Ains. 634 cents.=6 34

$6,34 Ans. N. B. When there are no pence in the given sum, you must annex two cyphers to the shillings; then divide as before, &c.

3. Reduce 31. 55. New-England currency, to Federal Money

8l. 5s.=65s. Then 6)6500

ents, 1083 Ans

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SOM USEXUL RULES,
VOR FINDING THIE CONTEXTS 02 SUPERFICIES

SOLIDS. SECTION 1. OF SUPERFICIES. The superficies or area of any plane surface, is composed or made up of saares, either greater or less, according to the different measures by which the dimensions of the figure are taken or measured :-and because 12 inches in length make 1 foot of long measure, thereCore, 12x12=144, the square inches in a superficiai foot, &c.

art. I. To find the area of a square having equal sides.

RULE. Multiply the side of the square into itself, and the product will be the area, or content.

1. How many square feet of bearils are contained in the floor of a room which is 20 feet square ?

20x20=400 fect, the Answer. 2. Suppose a square lot of land measures 20 rods on rach side, how many acres doth it contain ?

Nors.---160 square rods make all acre.
Therefore, 26%25= 676 sq. rous, and 676--100=4a.

56:. the fisuer. ART. 2. To measure a Parallelo rum, or long square.

EXAMPLES.

EXANIES,

Paultiply the length by the breadth, and the product will be the area or superficial content.

1. A certain garden, in form of a long square, is 96 ft. long, and 54 wide; how many square feet of ground are contained in it: Ans. 96X54=5194 square feet.

2. A lot of land, in form of a long square, is 120 rode in length, and 60 rods wide ; how many acres are in it?

120 x 60=7200 sf. rods, then, O=45 sores, fins.

3. If a board or plank be 21 feet long, and 18 inches broad; how many square feet are contained in it?

18 inches=1,5 me!, ten21x1,5=51,5 Ans.

Or, in measuring boards, yoriy multiply the length iu feet by the breadth ja inc!:es, and divide by 12, the quotient will give the answer in square feet, &c.

Thus, in the foregoing example, 21X18+12=31,5 as before.

4. If a board le 6 inches wide, how much in length will inake a square foot ?

RULE.--Divide 144 by the breacith, thus, 8)144

Ans. 18 in. 5. If a piece of land lie 5 rods wide, how many rous in length will make an acre ?

RULE.---Divide 160 by the breadth, and the quotient will be the length required, thus, 5)100

Ans. $2 rods in length. ART. 3. To measure a Triangle. Definition.- Triangle is any three cornered figure which is bounded by three right lines.*

RULE. Multiply the base of the given triangle into half its perpendicular height, or half the base into the whole perpendicular, and the product will be the area.

EXAMPLES.

1. Required the area of a triangle whose base or long. est side is S2 inches, and the perpendicular height 14 inches. 52x7=224 square inches, the Answer.

2. There is a triangular or three cornered lot of land whose base or longest side is 51 rods; the perpendicular from the corner opposite the base, measures 44 rods; how many acres doth it contain ?

51,5X29=1135 square rods, acres, 15 rods. *A Triangle may be either right angled or oblique; in either case the teacher can easily give the scholar a right idea of the base and perpendicular, by marking it dou'r on a slate, naper, foc

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