Elements of Geometry |
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Page 2
... parallel ( fig . 5 ) , when , being situated in the same plane and produced ever so far both ways , they do not meet . 13. A plane figure is a plane terminated on all sides by lines . If the lines are straight , the space which they ...
... parallel ( fig . 5 ) , when , being situated in the same plane and produced ever so far both ways , they do not meet . 13. A plane figure is a plane terminated on all sides by lines . If the lines are straight , the space which they ...
Page 4
... parallel Lines . THEOREM . 27. ALL right angles are equal . omit Demonstration . Let the straight line CD be perpendicular to Fig . 16. AB ( fig . 16 ) , and GH to EF , the angles ACD , EGH , will be equal . Take the four distances CA ...
... parallel Lines . THEOREM . 27. ALL right angles are equal . omit Demonstration . Let the straight line CD be perpendicular to Fig . 16. AB ( fig . 16 ) , and GH to EF , the angles ACD , EGH , will be equal . Take the four distances CA ...
Page 13
... parallel , that is , they will not meet , however far they are produced ( 12 ) . Demonstration . If they could meet in a point O on one side or the other of the line AB , there would be two perpendiculars drawn from the same point O to ...
... parallel , that is , they will not meet , however far they are produced ( 12 ) . Demonstration . If they could meet in a point O on one side or the other of the line AB , there would be two perpendiculars drawn from the same point O to ...
Page 14
... parallel . Demonstration . From the point G , the middle of AB , draw the straight line EGF perpendicular to AC ; this line will be perpen- dicular to BD . Indeed the sum GAE + CBD is , by hypothesis , equal to two right angles , and ...
... parallel . Demonstration . From the point G , the middle of AB , draw the straight line EGF perpendicular to AC ; this line will be perpen- dicular to BD . Indeed the sum GAE + CBD is , by hypothesis , equal to two right angles , and ...
Page 15
... parallel ( 57 ) . THEOREM . 61. If two straight lines , AI , BD ( fig . 36 ) , make with a third Fig . 36 . line AB two interior angles BAI , ABD , the sum of which is less than two right angles , the ... parallel Of Parallel Lines . 15.
... parallel ( 57 ) . THEOREM . 61. If two straight lines , AI , BD ( fig . 36 ) , make with a third Fig . 36 . line AB two interior angles BAI , ABD , the sum of which is less than two right angles , the ... parallel Of Parallel Lines . 15.
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Common terms and phrases
ABC fig adjacent angles altitude angle ACB angle BAD angles equal base ABCD bisect centre chord circ circular sector circumference circumscribed common cone consequently construction convex surface Corollary cube cylinder Demonstration diagonals diameter draw drawn equal and parallel equiangular equilateral equivalent faces figure four right angles frustum Geom gles greater hence homologous sides hypothenuse inclination inscribed circle intersection isosceles join less let fall line AC manner mean proportional measure the half meet multiplied number of sides oblique lines opposite parallelogram parallelopiped perimeter perpendicular plane MN polyedron prism proposition quadrilateral radii radius ratio rectangle regular polygon right angles right-angled triangle Scholium segment semicircumference side BC similar solid angle sphere spherical polygons spherical triangle square described straight line tangent THEOREM three plane angles triangle ABC triangular prism triangular pyramids vertex vertices whence
Popular passages
Page 65 - The square of the hypothenuse is equal to the sum of the squares of the other two sides ; as, 5033 402+302.
Page 21 - 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 ii - Co. of the said district, have deposited in this office the title of a book, the right whereof they claim as proprietors, in the words following, to wit : " Tadeuskund, the Last King of the Lenape. An Historical Tale." In conformity to the Act of the Congress of the United States...
Page 63 - 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 22 - CIRCLE is a plane figure bounded by a curved line, all the points of which are equally distant from a point within called the centre; as the figure ADB E.
Page ii - States entitled an act for the encouragement of learning hy securing the copies of maps, charts and books to the author., and proprietors of such copies during the times therein mentioned, and also to an act entitled an act supplementary to an act, entitled an act for the encouragement of learning by securing the copies of maps, charts and books to the authors and proprietors of such copies during the times therein mentioned and extending the benefits thereof to the arts of designing, engraving and...
Page 80 - The perimeters of two regular polygons of the same number of sides, are to each other as their homologous sides, and their areas are to each other as the squares of those sides (Prop.
Page 164 - If two triangles have two sides and the inchtded angle of the one respectively equal to two sides and the included angle of the other, the two triangles are equal in all respects.
Page 24 - In the same circle, or in equal circles, equal arcs are subtended by equal chords ; and, conversely, equal chords subtend equal arcs.
Page 153 - XVII.) ; hence two similar pyramids are to each other as the cubes of their homologous sides.