IN WENTWORTH'S GEOMETRY, REVISED EDITION, WITH SOLUTIONS. BOSTON, U.S.A., AND LONDON: Entered according to Act of Congress, in the year 1888, by G. A. WENTWORTH, in the Office of the Librarian of Congress at Washington. TYPOGRAPHY BY J. S. CUSHING & Co., BOSTON, U.S.A. PRESSWORK BY GINN & Co., BOSTON, U.S.A. PREFACE. THIS book is intended for teachers, and for them only. The pub lishers will sell it to no persons except teachers of Wentworth's Geometry. Every teacher must consider himself in honor bound not to leave his copy where pupils can have access to it, and not to sell his copy except to the publishers, Messrs. Ginn & Company. It is hoped that young teachers will derive great help from studying the systematic solutions of the exercises, and that every teacher who is pressed for time will find great relief by not being obliged to work out every problem himself. EXETER, N. H., 1888. G. A. WENTWORTH. TEACHERS' EDITION. Book I. Ex. 1. Find the value of an angle if it is double its complement; if it is one-fourth its complement. (1) Let x = the angle; then x + 90°; whence x = 60°. X (2) Let x = the angle; then x + 4x = 90°; whence x = 18°. Ex. 2. Find the value of an angle if it is double its supplement; if it 45°. (2) Let x = the angle; then x + 3x = 180°; whence x = Ex. 3. How many degrees in the angle formed by the hands of a clock at 2 o'clock? 3 o'clock? 4 o'clock? 6 o'clock? Ans. 60°, 90°, 120°, 180°. Ex. 4. If an angle is bisected, and if a line is drawn through the vertex perpendicular to the bisector, this line forms equal angles with the sides of the given angle. |