The First Six Books: Together with the Eleventh and TwelfthJ. Balfour, 1781 - 520 pages |
From inside the book
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Page 29
... reason , the ex- terior angle CEB of the triangle ABE is greater than BAC ; and it has been demonftrated that the angle BDC is greater than the angle CEB ; much more then is the angle BDC greater than the angle BAC . Therefore , if from ...
... reason , the ex- terior angle CEB of the triangle ABE is greater than BAC ; and it has been demonftrated that the angle BDC is greater than the angle CEB ; much more then is the angle BDC greater than the angle BAC . Therefore , if from ...
Page 73
... reason , CF is greater than GF : Again , because GF , FE are greater than EG , and EG is equal to ED ; GF , FE are greater than ED : Take away the common part FE , and the remainder GF is greater than the remainder FD : Therefore FA is ...
... reason , CF is greater than GF : Again , because GF , FE are greater than EG , and EG is equal to ED ; GF , FE are greater than ED : Take away the common part FE , and the remainder GF is greater than the remainder FD : Therefore FA is ...
Page 85
... reason , the angle FEC is double of A E a 5. I. b 32. I. C F the angle EAC : Therefore the whole angle BEC is double of the whole angle BAC . Again , Let E the centre of the circle be without the angle BDC , and join DE and produce it ...
... reason , the angle FEC is double of A E a 5. I. b 32. I. C F the angle EAC : Therefore the whole angle BEC is double of the whole angle BAC . Again , Let E the centre of the circle be without the angle BDC , and join DE and produce it ...
Page 86
... reason , the angle BFD is double of the angle BED : Therefore the angle BAD is equal to the angle BED . a 20. 3 . But , if the fegment BAED be not greater than a femicircle , let BAD , BED be angles in it ; these alfo are equal to one ...
... reason , the angle BFD is double of the angle BED : Therefore the angle BAD is equal to the angle BED . a 20. 3 . But , if the fegment BAED be not greater than a femicircle , let BAD , BED be angles in it ; these alfo are equal to one ...
Page 104
... reason , the angle ACB is equal to the angle DFE ; therefore the remaining angle BAC is equal to the remaining angle EDF : Wherefore the triangle ABC is equian- gular to the triangle DEF , and ' it is infcribed in the circle ABC . Which ...
... reason , the angle ACB is equal to the angle DFE ; therefore the remaining angle BAC is equal to the remaining angle EDF : Wherefore the triangle ABC is equian- gular to the triangle DEF , and ' it is infcribed in the circle ABC . Which ...
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Common terms and phrases
alfo alſo angle ABC angle BAC bafe baſe BC is equal BC is given becauſe the angle becauſe the ratio bifected Book XI cafe centre circle ABCD circumference cone confequently cylinder defcribed demonftrated drawn EFGH equal angles equiangular equimultiples Euclid excefs faid fame manner fame multiple fame ratio fame reafon fecond fegment fide BC fides fimilar firft firſt folid angle fome fore fphere fquare of AC ftraight line AB ftraight line BC given angle given ftraight line given in fpecies given in magnitude given in pofition given magnitude given ratio gnomon greater join lefs likewife oppofite parallel parallelepipeds parallelogram perpendicular plane angles prifms PROP propofition pyramid ratio of BC rectangle contained rectilineal figure right angles ſquare thefe THEOR theſe triangle ABC wherefore
Popular passages
Page 472 - The circumference of every circle is supposed to be divided into 360 equal parts, called degrees ; and each degree into 60 equal parts, called minutes ; and each minute into 60 equal parts, called seconds ; and these into thirds, &c.
Page 170 - If two triangles have one angle of the one equal to one angle of the other and the sides about these equal angles proportional, the triangles are similar.
Page 81 - THE straight line drawn at right angles to the diameter of a circle, from the extremity of...
Page 105 - DEF are likewise equal (13. i.) to two right angles ; therefore the angles AKB, AMB are equal to the angles DEG, DEF, of which AKB is equal to DEG ; wherefore the remaining angle AMB is equal to the remaining angle DEF.
Page 167 - AC the same multiple of AD, that AB is of the part which is to be cut off from it : join BC, and draw DE parallel to it : then AE is the part required to be cut off.
Page 10 - When a straight line standing on another straight line makes the adjacent angles equal to one another, each of the angles is called a right angle; and the straight line which stands on the other is called a perpendicular to it.
Page 62 - AB be the given straight line ; it is required to divide it into two parts, so that the rectangle contained by the whole, and one of the parts, shall be equal to the square of the other part.
Page 112 - To describe an equilateral and equiangular pentagon about a given circle. • Let ABCDE be the given circle; it is required to describe an equilateral and equiangular pentagon about the circle ABCDE. Let the angles of a pentagon, inscribed in the circle...
Page 200 - If two triangles have two angles of the one equal to two angles of the other, each to each, and one side equal to one side, viz. either the sides adjacent to the equal...
Page 38 - F, which is the common vertex of the triangles ; that is, together with four right angles. Therefore all the angles of the figure, together with four right angles, are equal to twice as many right angles as the figure has sides.