# Elements of Plane Geometry

American Book Company, 1901 - Geometry, Modern - 247 pages

### Contents

 Fourth proportional 404 9 Abbreviations list of 29 10 PRELIMINARY DEFINITIONS 12 Incommensurable quantities 342 18 Center of circle 19 Problem 23 Inscribed angle 354 29 RECTILINEAR FIGURES 44
 Quadrant 346 165 Corresponding angles 113 167 PROPORTIONS SIMILAR POLYGONS 168 vertical 75 173 Parallel lines 107 176 Quantities commensurable 342 179 BOOK IV 181 Pentagon 152 184

 BOOK II 79 sides of 13 109 Antecedents in proportion 404 119 ADDITIONAL EXERCISES 122 BOOK III 129 Converse 72 136 Median of a triangle 173 140 Corollary 25 142 Oblique angle 17 152
 Radius 20 190 Perpendicular lines 16 196 Point 5 214 Regular polygon 707 220 Apothem 716 223 Scalene triangle 18 228 Sector 343 238 AREAS OF POLYGONS 241 Copyright

### Popular passages

Page 68 - The straight line joining the middle points of two sides of a triangle is parallel to the third side, and equal to half of it.
Page 163 - If two chords intersect within a circle, the product of the segments of one is equal to the product of the segments of the other.
Page 129 - To express that the ratio of A to B is equal to the ratio of C to D, we write the quantities thus : A : B : : C : D ; and read, A is to B as C to D.
Page 120 - If a quadrilateral is circumscribed about a circle, the sum of one pair of opposite sides is equal to the sum of the other pair.
Page 72 - The lines joining the middle points of the opposite sides of a quadrilateral bisect each other.
Page 203 - In any obtuse triangle, the square of the side opposite the obtuse angle is equal to the sum of the squares of the other two sides, increased by twice the product of one of these sides and the projection of the other side upon it.
Page 15 - If two triangles have two sides and the included angle of one equal respectively to two sides and the included angle of the other, the triangles are equal.
Page 221 - Tangents to a circle at the middle points of the arcs subtended by the sides of a regular inscribed polygon...
Page 11 - PERIPHERY of a circle is its entire bounding line ; or it is a curved line, all points of which are equally distant from a point within called the center.
Page 61 - If the diagonals of a quadrilateral bisect each other, the figure is a parallelogram.