## An Introduction to the Theory and Practice of Plain and Spherical Trigonometry: And the Stereographic Projection of the Sphere : Including the Theory of Navigation ... |

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### Other editions - View all

An Introduction to the Theory and Practice of Plain and Spherical ... Thomas Keith No preview available - 2017 |

An Introduction to the Theory and Practice of Plain and Spherical ... Thomas Keith No preview available - 2014 |

An Introduction to the Theory and Practice of Plain and Spherical ... Thomas Keith No preview available - 2018 |

### Common terms and phrases

acute altitude Answer apparent base called centre chords circle Co-tang complement consequently construction contained COROLLARY cosec cosine declination describe diameter difference distance double draw drawn elevation equal equation Euclid EXAMPLE extent extreme fall feet formed formulę given gives greater half height hence horizontal hypothenuse latitude less logarithm longitude mean measure meridian middle miles natural North object oblique observed obtain obtuse opposite parallel perpendicular plane Plate pole primitive problem projected proportion PROPOSITION quadrant rad rad radius remainder represented right angles right ascension right-angled spherical RULE scale secant side side ac similar sine SOLUTION species sphere spherical triangle square star subtract sun's supplement suppose tang tangent third triangle ABC true vers versed sine yards

### Popular passages

Page 21 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds.

Page 2 - And if the given number be a proper vulgar fraction ; subtract the logarithm of the denominator from the logarithm of the numerator, and the remainder will be the logarithm sought ; which, being that of a decimal fraction, must always have a negative index.

Page 28 - The CO-SINE of an arc is the sine of the complement of that arc as L.

Page 107 - 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.

Page 31 - An angle at the circumference of a circle is measured by half the arc that subtends it. Let BAC be an angle at the circumference : it has for its measure half the arc "BC, which subtends it.

Page 136 - If two triangles have the three sides of the one equal to the three sides of the other, each to each, the triangles are congruent.

Page 258 - The HORIZON is a great circle which separates the visible half of the heavens from the invisible ; the earth being considered as a point in the centre of the sphere of the fixed stars.

Page 28 - The SECANT of an arc, is a straight line drawn from the center, through one end of the arc, and extended to the tangent which is drawn from the other end.

Page 27 - The sine, or right sine, of an arc, is the line drawn from one extremity of the arc, perpendicular to the diameter passing through the other extremity. Thus, BF is the sine of the arc AB, or of the arc BDE.