## Elements of Geometry |

### From inside the book

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... measure Fig . 64 , the half of the arc BD comprehended between its sides . Demonstration . Let us suppose , in the ... measure the arc BE ; therefore the angle BAC has for its

... measure Fig . 64 , the half of the arc BD comprehended between its sides . Demonstration . Let us suppose , in the ... measure the arc BE ; therefore the angle BAC has for its

**measure the half**of BE . For a simi- lar reason the angle CAD ... Page 40

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**measure the half**of the arc AKB ( 131 ) ; besides , the angle AMB , as an inscribed angle , has also for its**measure the half**of the arc AKB ; con- sequently the angle AMB = ABF = EBD = C ; therefore each of the angles inscribed in the ... Page 48

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**measure**EF × AL . But AL = DK ; and , since the triangle IBL is equal to the triangle KCI , the side BLCK ; therefore AB + CD = AL + DK = 2AL ; thus AL is**half**the sum of the sides AB , CD ; and consequently the area of the trapezoid ... Page 66

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**measure the half**of the arc AD , and the angle C has the same measure ; con- sequently the angle OAD = C ; therefore the two triangles are similar , and OC : OA :: OA : OD , which gives OA = OC × OD . --2 Fig . 133 . THEOREM . 229. In ... Page 72

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**measure**of the parallelogram , and XY is that of the square , therefore they are equivalent . 2. Let ABC ( fig . 144 ) be the given triangle , BC its base , and AD its altitude ; find a mean proportional between BC and**half**of AD , and ...### Other editions - View all

### Common terms and phrases

ABC fig adjacent angles altitude angle ACB angle BAD 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 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 pyramid S-ABC 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