### Contents

 INTRODUCTION 9 Propositions 21 BOOK II 47 BOOK III 57 Problems relating to the First and Third Books 76 BOOK IV 87 Problems relating to the Fourth Book 122 BOOK V 135
 Problems 267 Table of Natural Sines 273 Solution of Triangles 281 Solution of RightAngled Triangles 287 ANALYTICAL PLANE TRIGONOMETRY 297 of Formulas 306 Homogeneity of Terms 313 SPHERICAL TRIGONOMETRY 321

 BOOK VI 156 BOOK VII 174 BOOK VIII 202 BOOK IX 227 PAGE 245 PLANE TRIGONOMETRY 255 Multiplication by Logarithms 261
 Napiers Analogies 329 Of Quadrantal Triangles 335 MENSURATION OF SURFACES 347 Area of a Regular Polygon 353 PAGE 358 Convex Surface of a Cone 364

### Popular passages

Page 24 - If two triangles have two sides and the included angle of the one, equal to two sides and the included angle of the other, each to each, the two triangles will be equal.
Page 38 - That, if a straight line falling on two straight lines make the interior angles on the same side less than two right angles, the two straight lines, if produced indefinitely, meet on that side on which are the angles less than the two right angles.
Page 227 - A spherical triangle is a portion of the surface of a sphere, bounded by three arcs of great circles.
Page 271 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees...
Page 43 - Hence, the interior angles plus four right angles, is equal to twice as many right angles as the polygon has sides, and consequently, equal to the sum of the interior angles plus the sum of the exterior angles.
Page 215 - The surface of a sphere is equal to the product of its diameter by the circumference of a great circle.
Page 107 - If two triangles have two angles of the one equal to two angles of the other, each to each, and also one side of the one equal to the corresponding side of the other, the triangles are congruent.
Page 93 - The area of a parallelogram is equal to the product of its base and altitude.
Page 231 - The angles of spherical triangles may be compared together, by means of the arcs of great circles described from their vertices as poles and included between their sides : hence it is easy to make an angle of this kind equal to a given angle.
Page 232 - F, be respectively poles of the sides BC, AC, AB. For, the point A being the pole of the arc EF, the distance AE is a 'quadrant ; the point C being the pole of the arc DE, the distance CE is likewise a quadrant : hence the point E is...