## The Elements of Euclid: Viz. the First Six Books, Together with the Eleventh and Twelfth. The Errors, by which Theon, Or Others, Have Long Ago Vitiated These Books, are Corrected, and Some of Euclid's Demonstrations are Restored. Also, the Book of Euclid's Data, in Like Manner Corrected |

### From inside the book

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Page 11

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**perpendicular**to it . XI . An obtuse angle is that which is greater than a right angle . XII . An acute angle is that which is less than a right angle . ' XIII . " A term or boundary is the extremity of any thing . " XIV . A figure is ... Page 21

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**perpendicular**to a given straight line of an unlimited length , from a given point without it . Let AB be the given straight line , which may be produced to any length both ways , and let C be a point without it . It is re- quired to ... Page 61

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**perpendicular**falls , and the straight line intercepted without the trian- gle between the**perpendicular**and the obtuse angle . Let ABC be an obtuse angled triangle , having the obtuse an- gle ACB , and from the point A let AD be drawn ... Page 62

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**perpendicular**let fall upon it from the oppo- site angle , and the acute angle . * Let ABC be any triangle , and the angle at B one of its acute angles , and upon BC , one of the sides containing it , let fall the**perpendicular**( 12 ... Page 63

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**perpendicular**to BC ; then is BC the straight line between the perpendi- cular and the acute angle at B ; and it is manifest that the square of AB , BC are equal ( 47. 1. ) to the square of AC and twice the square of BC . There- fore ...### Other editions - View all

The Elements of Euclid: Viz, the First Six Books, Together with the Eleventh ... Robert Simson,Euclid Euclid No preview available - 2018 |

### Common terms and phrases

altitude angle ABC angle BAC base BC BC is equal BC is given bisected centre circle ABCD circumference cone cylinder demonstrated described diameter draw drawn equal angles equiangular equimultiples Euclid ex æquali excess fore given angle given in magnitude given in position given in species given magnitude given ratio given straight line gnomon greater join less Let ABC meet multiple parallel parallelogram parallelogram AC perpendicular point F polygon prism proportionals proposition Q. E. D. PROP radius ratio of AE rectangle CB rectangle contained rectilineal figure remaining angle right angles segment sides BA similar sine solid angle solid parallelopipeds square of AC straight line AB straight line BC tangent THEOR third triangle ABC triplicate ratio vertex wherefore