Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books |
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Page 20
The First Six, the Eleventh and Twelfth Books Euclid. If therefore a right line ftanding upon a right line makes angles , thefe angles fhall either be two right angles , or [ both together ] equal to two right angles . Which was to be ...
The First Six, the Eleventh and Twelfth Books Euclid. If therefore a right line ftanding upon a right line makes angles , thefe angles fhall either be two right angles , or [ both together ] equal to two right angles . Which was to be ...
Page 21
... right lines , drawn contrary ways , do make with the firft line the ad- jacent angles equal to two right angles , thofe right lines will be directly placed to one another , or both fall into one right line . Which was to be demonstrated ...
... right lines , drawn contrary ways , do make with the firft line the ad- jacent angles equal to two right angles , thofe right lines will be directly placed to one another , or both fall into one right line . Which was to be demonstrated ...
Page 22
... angles at the point of interfection equal to four right angles . PROP . XVI . THEOR . Any one fide of every triangle being produced , the out- ward angle is greater than either of the inward oppofite angles . Let the triangle be BA C ...
... angles at the point of interfection equal to four right angles . PROP . XVI . THEOR . Any one fide of every triangle being produced , the out- ward angle is greater than either of the inward oppofite angles . Let the triangle be BA C ...
Page 23
... angles . Which was to be demonftrated , PROP . XVII . THEOR . Any two angles of every triangle taken together , are lefs than two right angles . Let there be a triangle ABC : I fay , any two angles of the triangle A B C taken together ...
... angles . Which was to be demonftrated , PROP . XVII . THEOR . Any two angles of every triangle taken together , are lefs than two right angles . Let there be a triangle ABC : I fay , any two angles of the triangle A B C taken together ...
Page 33
... angle AGH is equal to the remaining angle G H D ; and they are alternate angles : Therefore A B [ by prop . 27. ] is parallel to c D. D If If therefore a right line falling upon two right lines Book I. 33 Euclid's Elements .
... angle AGH is equal to the remaining angle G H D ; and they are alternate angles : Therefore A B [ by prop . 27. ] is parallel to c D. D If If therefore a right line falling upon two right lines Book I. 33 Euclid's Elements .
Other editions - View all
Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books Euclid,David Gregory No preview available - 2023 |
Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books Euclid,David Gregory No preview available - 2023 |
Euclid's Elements of Geometry: The First Six, the Eleventh and Twelfth Books Euclid,David Gregory No preview available - 2016 |
Common terms and phrases
A B C D alfo alſo angle ABC becauſe the angle bifected centre circle A B C circumference cone confequent cylinder defcribed demonftrated diameter equal angles equiangular equimultiples Euclid EUCLID's ELEMENTS fame altitude fame multiple fame ratio fame reafon fecond fegment femidiameter fhall fides A B fimilar fince firft firſt fixth folid angle folid parallelepipedon fome fphere ftand given circle given right line given triangle greater infcribed interfect join leffer lefs leſs parallel parallelogram perpendicular polygon prifm PROP propofition proportional pyramid rectangle contained regular polygon remaining angle right angles right line A B right lined figure right-lined SCHOLIUM ſquare thefe THEOR theſe thofe thoſe trapezium triangle ABC twice the fquare vertex the point Wherefore whofe bafe whoſe baſe
Popular passages
Page 247 - 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 30 - 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 248 - But it was proved that the angle AGB is equal to the angle at F ; therefore the angle at F is greater than a right angle : But by the hypothesis, it is less than a right angle ; which is absurd.
Page 18 - When a straight line set up on a straight line makes the adjacent angles equal to one another, each of the equal angles is right, and the straight line standing on the other is called a perpendicular to that on which it stands.
Page 32 - Let the straight line EF, which falls upon the two straight lines AB, CD, make the alternate angles AEF, EFD equal to one another; AB is parallel to CD.
Page 56 - 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.
Page 391 - KL: but the cylinder CM is equal to the cylinder EB, and the axis LN to the axis GH; therefore as the cylinder EB to...
Page 110 - If any two points be taken in the circumference of a circle, the straight line which joins them shall fall within the circle.
Page 130 - When you have proved that the three angles of every triangle are equal to two right angles...
Page 183 - FK : in the same manner it may be demonstrated, that FL, FM, FG are each of them equal to FH, or FK : therefore the five straight lines FG, FH, FK, FL, FM are equal to one another : wherefore the circle described from the centre F, at the distance of...