## Inventional Geometry: A Series of Problems, Intended to Familiarize the Pupil with Geometrical Conceptions, and to Exercise His Inventive Faculty |

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### Common terms and phrases

adjacent angles angular points arc is called arithmetic mean arrange the surfaces axis base breadth card a hollow circumference cone construct cube curve determine diagonal scale diameter dimensions distance divide a circle divide a line divide an equilateral dodecagon duodecimals ellipse equal and similar equal sectors equilateral triangle find the area four equal frustum geometry Give a plan give a sketch Give an example gles HERBERT SPENCER hexahedron icosahedron isosceles triangle line drawn line of chords line of sines line of tangents line parallel measure nonagon number of degrees oblate spheroid obtuse angle octagon octahedron pentagon piece of card place a circle place a hexagon place a square polygon protractor pupil pyramid quadrant quadrilaterals radii radius reëntrant angle rhomboid rhombus right-angled triangle secant sides is called solid square inches square whose side square yard takes the name tetrahedron trapezium triangle whose sides versed sine write its name zoid

### Popular passages

Page 43 - TRIANGLES upon the same base, and between the same parallels, are equal to one another.

Page 5 - WHEN it is considered that by geometry the architect constructs our buildings, the civil engineer our railways ; that by a higher kind of geometry, the surveyor makes a map of a county or of a kingdom ; that a geometry still higher is the foundation of the noble science of the astronomer, who by it not only determines the diameter of the globe he lives upon, but as well the sizes of the sun, moon, and planets, and their distances from us and from each other; when it is considered, also, that by this...

Page 62 - ... equally long and narrow parallel spaces, cut at equal intervals by lines at right angles to them, with a spare end division subdivided similarly, only at right angles to the other divisions, into ten small rectangles, each of which small rectangles, being provided with a diagonal, is called a diagonal scale. 24:6. Make a diagonal scale that shall express a number consisting of three digits. 247. With the assistance of a diagonal scale, construct a plan of a rectangular piece of ground, whose...

Page 13 - I keep the subject constantly before me, and wait till the first dawnings open slowly by little and little into a full and clear light.

Page 83 - Can you divide a common triangle into two equal parts by a line parallel to one of its 376. Can you divide a triangle into two equal parts by a line from any point in any one of its sides ? 377. Show how many solid feet there are in a solid yard. 378. Make an oblique square prism with two rectangular sides and two rhomboidal sides. 379. Make an oblique square prism with all its sides...

Page 5 - INTRODUCTION. it is considered that by geometry the architect constructs our buildings, the civil engineer our railways; that by a higher kind of geometry, the surveyor makes a map of a county or of a kingdom; that a geometry still higher is the foundation of the noble science of the astronomer, who by it not only determines the diameter of the globe he lives upon, but as well the sizes of the sun, moon, and planets, and their distances from us and from each other; when it is considered...

Page 3 - ... TAPPAN, MA ROBINSON'S NEW GEOMETRY AND TRIGONOMETRY. 8vo, calf. 453 pages $1.60 Embracing plane and solid geometry, and plane and spherical trigonometry, with numerous practical problems. SPENCER'S INVENTIONAL GEOMETRY. (Science Primer Series.) By WM. GEO. SPENCER.

Page 4 - To its great efficiency, both as a means of providing interest in geometry, and as a mental discipline, I can give personal testimony. I have seen it create in a class of boys so much enthusiasm that they looked forward to their geometry lesson as a chief event in the week. And girls, initiated in the system by my father, have frequently begged of him for problems to solve during the holidays.

Page 47 - Make of one piece of card a hollow octahedron : show how you arrange the surfaces go as to fold together correctly; and give a sketch of the octahedron. 162. Can you divide an angle into four equal angles, without using more than four circles ? 163. In how many ways can you divide an equilateral triangle into three parts, that shall be equal to each other, and similar to each other ? 164. Given an arc of a circle : it is required to find the centre of the circle of which it is an arc. 165. Can you...

Page 2 - Congress, to the year 1876, BY D. APPLETON & CO., In the Office of the Librarian of Congress, at Washington. PREFACE TO THE AMERICAN EDITION. THIS little book, prepared by an experienced mathematical teacher for the use of his own pupils, is based upon the principle that the best and only true education is self-education.