### Contents

 RATIO AND PROPORTION 43 BOOK III 55 PROPORTIONS AREAS AND SIMILARITY OF FIGURES 76 PROBLEMS RELATING TO THE PRECEDING BOOKS 118 BOOK VI 142 SOLID GEOMETRY 165 BOOK VIII 184 THE SPHERE AND ITS PROPERTIES 214
 BOOK XII 281 BOOK XIII 301 BOOK XIV 311 TRIGONOMETRY 1 BOOK II 13 BOOK IV 61 BOOK V 72 165 77

 THE THREE ROUND BODIES 239 BOOK XI 253

### Popular passages

Page 35 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
Page 57 - 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 117 - Through a given point to draw a straight line parallel to a given straight line, Let A be the given point, and BC the given straight line : it is required to draw through the point A a straight line parallel to BC.
Page 50 - If any number of magnitudes are proportional, any antecedent is to its consequent as the sum of all the antecedents is to the sum of all the consequents. Let A : B : : C : D : : E : F; then will A : B : : A + C + E : B + D + F.
Page 77 - Two rectangles having equal altitudes are to each other as their bases.
Page 158 - If a straight line is perpendicular to each of two straight lines at their point of intersection, it is perpendicular to the plane of those lines.
Page 313 - FRACTION is a negative number, and is one more tftan the number of ciphers between the decimal point and the first significant figure.
Page 314 - The logarithm of any POWER of a number is equal to the product of the logarithm of the number by the exponent of the power. For let m be any number, and take the equation (Art.
Page 100 - The areas of two triangles which have an angle of the one equal to an angle of the other are to each other as the products of the sides including the equal angles. A D A' Hyp. In triangles ABC and A'B'C', To prove AABC A A'B'C' A'B' x A'C ' Proof. Draw the altitudes BD and B'D'.
Page 244 - RULE. — Multiply the base by the altitude, and the product will be the area.