## The First Six Books: Together with the Eleventh and Twelfth |

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Page 5

But , by often confidering and com- paring together the Definitions and Demonftrations as they are in the Greek Editions we now have , I found that Theon , or whoever was the Editor of the prefent Greek , Text , by

But , by often confidering and com- paring together the Definitions and Demonftrations as they are in the Greek Editions we now have , I found that Theon , or whoever was the Editor of the prefent Greek , Text , by

**adding**fome things ... Page 7

In this Sixth Edition , Ptolemy's Propofition concerning a Pro- perty of quadrilateral Figures in a Circle is

In this Sixth Edition , Ptolemy's Propofition concerning a Pro- perty of quadrilateral Figures in a Circle is

**added**at the End of the fixth Book . Alfo the Note on the 29th Prop . Book ift , is altered , and made more explicit , and a ... Page 13

If equals be

If equals be

**added**to equals , the wholes are equal . III . If equals be taken from equals , the remainders are equal IV . If equals be**added**to unequals , the wholes are unequal . V. If equals be taken from unequals , the remainders ... Page 58

... XH make up the fi gure AEFD which is the fquare of AD : Therefore four times the rectangle AB , BC . together with the fquare of AC , is e- qual to the fquare of AD , that is , of AB and BC

... XH make up the fi gure AEFD which is the fquare of AD : Therefore four times the rectangle AB , BC . together with the fquare of AC , is e- qual to the fquare of AD , that is , of AB and BC

**added**toge- ther in one ftraight line . Page 112

It is alfo equiangular ; because the cir cumference AB is equal to the circumference DE : If to each be

It is alfo equiangular ; because the cir cumference AB is equal to the circumference DE : If to each be

**added**BCD , the whole ABCD is equal to the whole EDCB : And the angle AED ftands on the circumference ABCD , and the angle BAE on ...### What people are saying - Write a review

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### Common terms and phrases

added alfo alſo altitude angle ABC angle BAC bafe baſe becauſe bifected Book Book XI centre circle circle ABCD circumference common cone cylinder defcribed definition demonftrated diameter divided double draw drawn equal equal angles equiangular equimultiples excefs fame fame multiple fecond fegment fhall fides fimilar firft folid folid angle fore four fourth fquare fquare of AC ftraight line given angle given in fpecies given in pofition given magnitude given ratio greater Greek half join lefs magnitude meet oppofite parallel parallelogram perpendicular plane prifms produced PROP propofition proportionals pyramid rectangle rectangle contained remaining right angles Take taken thefe THEOR theſe third triangle ABC wherefore whole

### Popular passages

Page 474 - 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.