### Contents

 ELEMENTARY PRINCIPLES 7 BOOK II 43 BOOK III 55 BOOK IV 76 BOOK V 118 BOOK VI 142 SOLID GEOMETRY 165 BOOK VIII 184
 BOOK X 238 BOOK XII 281 BOOK XIII 301 BOOK XIV 311 TRIGONOMETRY 1 BOOK II 13 BOOK IV 61 BOOK V 72

 BOOK IX 214
 BOOK VI 105

### Popular passages

Page 19 - In an isosceles triangle, the angles opposite the equal sides are equal.
Page 59 - 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 172 - If two planes are perpendicular to each other, a straight line drawn in one of them, perpendicular to their common section, will be perpendicular to the other plane.
Page 103 - 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 215 - A SPHERICAL TRIANGLE is a portion of the surface of a sphere bounded by three arcs of great circles, each arc being less than a semi-circumference ; as AE D.
Page 23 - Any side of a triangle is less than the sum of the other two sides...
Page 37 - 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 120 - At a point in a given straight line to make an angle equal to a given angle.
Page 254 - To find the area of a PARALLELOGRAM. Multiply the base by the altitude, and the product will be the area (Prop.
Page 94 - In any quadrilateral the sum of the squares of the sides is equivalent to the sum of the squares of the diagonals, plus four times the square of the straight line that joins the middle points of the diagonals.