## Elements of Geometry and Trigonometry |

### From inside the book

Results 1-5 of 33

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**gles**right - angles . The rectangle , which has its angles right an-**gles**, without having its sides equal . The parallelogram , or rhomboid , which has its opposite sides parallel . The rhombus , or lozenge , which has its sides equal ... Page 14

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**gles**ACE , ECD : therefore ACD + DCB is the sum of the three angles ACE , ECD , DCB : but the first of these three angles is a right angle , and the other two make up the right angle ECB ; hence , the sum of the two an-**gles**ACD and DCB ... Page 25

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**gles**BAC , ABD , together equal to two right angles : then the lines EC , BD , will be parallel . B E A C F D From G , the middle point of BA , draw the straight line EGF , perpendicular to EC . It will also be perpendicular to BD . For ... Page 26

... + GOC , be equal to two right an-

... + GOC , be equal to two right an-

**gles**. For , if OGB + GOD be not equal to two right angles , let IGH be drawn , making the sum OGH + GOD equal to two A I F E B H D right angles ; then IH and CD will be parallel 26 GEOMETRY . Page 27

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**gles**then will IH and CD meet if sufficiently produced . For , if they do not meet they are parallel ( Def.12 . ) . But they are not parallel , for if they were , A E I G B H D F the sum of the interior angles OGH , GOD , would be equal ...### Other editions - View all

### Common terms and phrases

adjacent adjacent angles altitude angle ACB angle BAC ar.-comp base multiplied bisect Book centre chord circ circumference circumscribed common cone convex surface Cosine Cotang cylinder diagonal diameter dicular distance draw drawn equal angles equally distant equiangular equivalent figure formed four right angles frustum given angle given line gles greater homologous sides hypothenuse inscribed polygon intersection less Let ABC let fall logarithm measured by half number of sides oblique lines opposite parallelogram parallelopipedon pendicular perimeter perpen perpendicular plane MN polyedron polygon ABCDE prism proportional PROPOSITION pyramid quadrant quadrilateral quantities radii radius ratio rectangle regular polygon right angled triangle S-ABC Scholium secant secant line segment side BC similar sine solid angle solid described sphere spherical polygon spherical triangle square described straight line tang tangent THEOREM triangle ABC triangular prism vertex