The First Six Books of the Elements of Euclid, with a Commentary and Geometrical Exercises: To which are Annexed a Treatise on Solid Geometry, and a Short Essay on the Ancient Geometrical AnalysisJohn Taylor, 30 Upper Gower Street, Bookseller and Publisher to the University: and sold, 1828 - Euclid's Elements - 324 pages |
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Page 4
... angle is the inclination of two right lines to one another , which meet together , but are not in the same right line . X. When a right line standing on another right line makes the adjacent angles equal , each of these angles is called a ...
... angle is the inclination of two right lines to one another , which meet together , but are not in the same right line . X. When a right line standing on another right line makes the adjacent angles equal , each of these angles is called a ...
Page 5
... angles are therefore equal when they admit of superposition . This may be determined thus ; if the angles A B C and ... right angle . An angle is sometimes expressed simply by the letter placed at its vertex , as we have done in comparing the ...
... angles are therefore equal when they admit of superposition . This may be determined thus ; if the angles A B C and ... right angle . An angle is sometimes expressed simply by the letter placed at its vertex , as we have done in comparing the ...
Page 8
... right - angled triangle is that which has a right angle . That side of a right - angled triangle which is opposite to the right angle is called the hypotenuse . ( 32 ) ( 33 ) XXVIII . An obtuse - angled triangle is that which has an obtuse ...
... right - angled triangle is that which has a right angle . That side of a right - angled triangle which is opposite to the right angle is called the hypotenuse . ( 32 ) ( 33 ) XXVIII . An obtuse - angled triangle is that which has an obtuse ...
Page 11
... right angles are equal . B If two right lines ( A B , C D ) meet a third right line ( AC ) so as to make the two interior angles ( B A C and DCA ) on the same side less than two right angles , these two right lines will meet if they be ...
... right angles are equal . B If two right lines ( A B , C D ) meet a third right line ( AC ) so as to make the two interior angles ( B A C and DCA ) on the same side less than two right angles , these two right lines will meet if they be ...
Page 12
... right line can be drawn between two given points . For if two different right lines could be drawn from one given ... angles BAC and BAD are equal by ( 11 ) , as also the right angles FEG and FEH . But to prove that the right angle FE G ...
... right line can be drawn between two given points . For if two different right lines could be drawn from one given ... angles BAC and BAD are equal by ( 11 ) , as also the right angles FEG and FEH . But to prove that the right angle FE G ...
Other editions - View all
The First Six Books of the Elements of Euclid: With a Commentary and ... Dionysius Lardner No preview available - 2018 |
Common terms and phrases
A B and B C A B D altitude angles A B C arcs Book centre circumference circumscribed coincide conical surface constructed demonstration diagonal diameter difference draw equal angles equal hyp equal sides equi equiangular equilateral triangle equimultiples Euclid external angle extremities geometry given circle given line given point given right line Hence homologous sides hypotenuse inscribed intersect isosceles triangle less magnitudes multiple opposite parallel parallelogram parallelopiped pentagon perpendicular plane polygon prism problem produced PROPOSITION proved pyramid radii radius rectangle rectilinear figure respectively equal right line A B segments sides A B similar solid angle square of A B surface tangent THEOREM third tiples triangles A B C vertex
Popular passages
Page 16 - If two triangles have two sides of the one respectively equal to two sides of the other, and the contained angles supplemental, the two triangles are equal.
Page 24 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
Page 22 - DE : but equal triangles on the same base and on the same side of it, are between the same parallels ; (i.
Page 104 - ... be equimultiples, the one of the second, and the other of the fourth. Let A the first be the same multiple of B the second, that C the third is of D the fourth ; and of A, C let equimultiples EF, GH be taken.
Page 107 - ... If there be three magnitudes, and other three, which have the same ratio taken two and two, but in a cross order; then if the first magnitude be greater than the third, the fourth shall be greater than the sixth: and if equal, equal; and if less, less.
Page 107 - N ; and if equal, equal ; and if less, less : but if G be greater than L, it has been shown that L HC K E M F N H is greater than M ; and if equal, equal; and if less, less: therefore, if G be greater than L, K is greater than N ; and if equal, equal ; and if less less : and G, K are any equimultiples whatever of A, E ; and L, N any whatever of B, F : therefore as A is to B, so is E to F (5.
Page 187 - If two angles of one triangle are equal to two angles of another triangle, the third angles are equal, and the triangles are mutually equiangular.
Page 107 - IF the first be to the second as the third to the fourth, and if the first be a multiple, or part of the second; the third is the same multiple, or the same part of the fourth...
Page 107 - THEOR. IF the first be the same multiple of the second, or the same part of it, that the third is of the fourth ; the first is to the second, as the third is to the fourth...
Page 107 - D (as in fig. 2 and 3), this magnitude can be multiplied, so as to become greater than D, whether it be AC, or CB. Let it be multiplied until it...