## An Elementary Geometry |

### From inside the book

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**adjacent**angles equal , each of these angles is a right angle ; and the two lines are perpendicular to each other . Thus , ACD and D C B , being equal , are right an- gles , and AB and DC are perpendicular to each other . 3. An Acute ... Page 5

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**adjacent**angles equal to two right angles , these two lines form a straight line . Let the straight line DB meet the two lines , AB , BC , so as to make ABD + DBC = two right angles : then AB and BC form a straight line . A- B D E C For ... Page 7

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**adjacent**, are called alternate internal angles ; as A G H and G H D , or B G H and G H C. Two angles , one external , one internal , on the same side of the secant , and not**adjacent**, are called opposite external and in- ternal angles ... Page 17

... ; as QRST . P R S T U Ꮴ 60. A Rhombus is an equilateral rhomboid ; as U V W X. X W 61. A Diagonal is a line joining the vertices of two angles . not

... ; as QRST . P R S T U Ꮴ 60. A Rhombus is an equilateral rhomboid ; as U V W X. X W 61. A Diagonal is a line joining the vertices of two angles . not

**adjacent**; as DB . THEOREM XVII . 62. The opposite sides and angles of BOOK I. 17. Page 24

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**adjacent**angles of a parallelogram are perpendicular to each other . 92. From the vertices of a parallelogram measure equal distances upon the sides in order . The lines joining these points on the sides form a parallelogram . 93. Prove ...### Other editions - View all

### Common terms and phrases

A B C A B D ABCD adjacent adjacent angles altitude angle ABC apothem base and altitude centre chord circ circumference cone construct the triangle convex surface Corollary cylinder diagonals diameter distance divided dodecagon equal altitudes equally distant equilateral feet frustum given angle given circle given line given point given side half the arc hexagon homologous sides hypothenuse included angle infinite number inscribed internal angles intersection isosceles triangle Let ABCDEF line joining lines A B measured by half mutually equiangular number of sides opposite sides parallelogram parallelopiped perimeter perpendicular plane parallel quadrilateral radii radius ratio rectangle regular polygon respectively equal rhombus right angles right prism right pyramid right triangle Scholium secant segment similar triangles slant height sphere tangent THEOREM VII trapezoid triangle ABC triangles are equal vertex