The First Six Books: Together with the Eleventh and TwelfthJ. Balfour, 1781 - 520 pages |
From inside the book
Results 6-10 of 100
Page 196
... plane , when it makes right angles with every straight line meeting it in that plane . IV . A plane is perpendicular to a plane , when the straight lines drawn in one of the planes perpendicularly to the common fection of the two planes ...
... plane , when it makes right angles with every straight line meeting it in that plane . IV . A plane is perpendicular to a plane , when the straight lines drawn in one of the planes perpendicularly to the common fection of the two planes ...
Page 197
... planes . XII . A pyramid is a folid figure contained by planes that are confti- tuted betwixt one plane and one point above it in which they meet . XIII . Á prism is a folid figure contained by plane figures of which two that are ...
... planes . XII . A pyramid is a folid figure contained by planes that are confti- tuted betwixt one plane and one point above it in which they meet . XIII . Á prism is a folid figure contained by plane figures of which two that are ...
Page 199
... plane and see N. another part above it . If it be poffible , let AB , part of the the plane , and the part BC above it : line AB is in the plane , it can be produced in that plane : Let it be produced to D : And let any plane pafs thro ...
... plane and see N. another part above it . If it be poffible , let AB , part of the the plane , and the part BC above it : line AB is in the plane , it can be produced in that plane : Let it be produced to D : And let any plane pafs thro ...
Page 200
... plane BC the ftraight line DFB : Then two straight lines DEB , DFB have the fame extremi- ties , and therefore ... plane which paffes through them , that is , to the plane in which they are . Let the ftraight line EF ftand at right ...
... plane BC the ftraight line DFB : Then two straight lines DEB , DFB have the fame extremi- ties , and therefore ... plane which paffes through them , that is , to the plane in which they are . Let the ftraight line EF ftand at right ...
Page 201
... plane paffing through AB , CD . In like manner , it may be proved , that FE makes right angles with every ftraight line which meets it in that plane . But a ftraight line is at right angles to a plane when it makes right angles with ...
... plane paffing through AB , CD . In like manner , it may be proved , that FE makes right angles with every ftraight line which meets it in that plane . But a ftraight line is at right angles to a plane when it makes right angles with ...
Other editions - View all
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.