A Treatise of Practical Surveying: Which is Demonstrated from Its First Principles. Wherein Every Thing that is Useful and Curious in that Art, is Fully Considered and Explained ... The Whole Illustrated with CopperplatesP. Wogan, 1795 - 319 σελίδες |
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Σελίδα 18
... perpendicular Line let fall from one End thereof , to a Diameter drawn to the other End : Thus HL is the right Sine of the Arc HB . The Sines on the fame Diameter encrease till they come to the Center , and fo become the Ra- dius Hence ...
... perpendicular Line let fall from one End thereof , to a Diameter drawn to the other End : Thus HL is the right Sine of the Arc HB . The Sines on the fame Diameter encrease till they come to the Center , and fo become the Ra- dius Hence ...
Σελίδα 19
... perpendicular to the End of the Diameter , and is terminated by a Line drawn from the Center thro ' the other End : Thus BK is the Tangent of the Arc HB . Fig . 8 . 25. And the Line which terminates the Tan- gent that is CK , is called ...
... perpendicular to the End of the Diameter , and is terminated by a Line drawn from the Center thro ' the other End : Thus BK is the Tangent of the Arc HB . Fig . 8 . 25. And the Line which terminates the Tan- gent that is CK , is called ...
Σελίδα 22
... perpendicular Height of a Triangle is a Line drawn from the Vertex to the Base , perpen- dicularly : Thus if the Triangle ABC be propof- ed , and BC be made its Bafe , then if from the Vertex A the Perpendicular AD be drawn to BC , the ...
... perpendicular Height of a Triangle is a Line drawn from the Vertex to the Base , perpen- dicularly : Thus if the Triangle ABC be propof- ed , and BC be made its Bafe , then if from the Vertex A the Perpendicular AD be drawn to BC , the ...
Σελίδα 26
... perpendicular to CD , then ( by Def . 11. ) the Angles CBA , and ABD , will be each a right Angle . 2. But if EB fall flantwife on CD , then are the Angles DBE + EBC = DBE + EBA ( = DBA ) + ABC , or to two right Angles . Q. E. D. ...
... perpendicular to CD , then ( by Def . 11. ) the Angles CBA , and ABD , will be each a right Angle . 2. But if EB fall flantwife on CD , then are the Angles DBE + EBC = DBE + EBA ( = DBA ) + ABC , or to two right Angles . Q. E. D. ...
Σελίδα 30
... Perpendicular CD on the Chord AB , it will bifect it in the Point D. Fig . 29 . Let the Lines CA and CB be drawn from the Center to the Extremities of the Chord , then fince CA = CB , the Angle CAB = CBA ( by the Lem- ma ) . But the ...
... Perpendicular CD on the Chord AB , it will bifect it in the Point D. Fig . 29 . Let the Lines CA and CB be drawn from the Center to the Extremities of the Chord , then fince CA = CB , the Angle CAB = CBA ( by the Lem- ma ) . But the ...
Συχνά εμφανιζόμενοι όροι και φράσεις
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Δημοφιλή αποσπάσματα
Σελίδα 13 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees; and each degree into 60 minutes, each minute into 60 seconds, and so on.
Σελίδα 88 - C' (89) (90) (91) (92) (93) 112. In any plane triangle, the sum of any two sides is to their difference as the tangent of half the sum of the opposite angles is to the tangent of half their difference.
Σελίδα 56 - ... logarithm of that number. EXAMPLE. • Required, the logarithm of 365. Answer, 2.56229. And though most tables of logarithms run but to 10000, yet by them the log. of any number not exceeding 10,000,000 may be found, and on the contrary, the number to any such logarithm, thus : 1 Find the log. of the first four figures of the given number 2. Take that log. from the log: of the number next following, and note their difference, 3. Multiply that difference by the remaining figures of the given number...
Σελίδα 91 - In the triangle ABC, there is given AB 240, the angle A 46° 30', and BC 200, to find the angle C, being acute, the angle B, and the side AC.
Σελίδα 89 - ED. that is as the sum of the two sides AB and BC, is to their difference ; so is the tangent of half the sum of the two unknown angles A and C, to the tangent of half their difference.
Σελίδα 32 - KCML, the sum of the two parallelograms or square BCMH ; therefore the sum of the squares on AB and AC is equal to the square on BC.
Σελίδα 19 - Four quantities are said to be in proportion when the product of the extremes is equal to that of the means, thus if A multiplied by D, be equal to B multiplied by C, then A is said to be to B as C is to D. POSTULATES OR PETITIONS. 1 . That a right line may be drawn from any one given point to another. 2. That a right line may be produced or continued at pleasure. 3. That from any centre and with any radius, the circumference of a circle may be described.
Σελίδα 13 - A chord is a right line drawn from one end of an arc or arch (that is, any part of the circumference of a circle) to the other ; and is the measure of the arc. Thus the right line HG, is the measure of the arc HBG.
Σελίδα 72 - ... these three proportions, for DE we put its equal be, for AE put ab, and for AD put ac, they will become AB : ab : : AC : ас, and AB : ab : : BC : be, and AC : ac : : BC : be.
Σελίδα 285 - Then if the true and magnetic amplitudes, be both north or both south, their difference is the variation ; but if one be north and the other south, their sum is the variation ; and to know whether it be easterly or westerly, suppose the observer looking...