 | J. G - 1878 - 408 pages
...line, may always be drawn from a given point in a given plane perpendicular to that plane." (5) // two straight lines be at right angles to the same plane they shall be parallel to one another. If two straight lines be paraUtl, and one of tfiem be at right angles to a plane, the other also shall... | |
 | University of Madras - 1879 - 674 pages
...parallelepipeds and tetrahedrons are particular cases of other solids denned by Euclid. Shew this. IX. If two straight lines be at right angles to the same plane they shall be parallel to one another. X. If two straight lines meeting one another be parallel to two others that meet one another and are... | |
 | Isaac Todhunter - Euclid's Elements - 1880 - 426 pages
...BC, BD, BE are in one and the same plane. Wherefore, if three straight linet &c. QEB PROPOSITION C. THEOREM. If two straight lines be at right angles...CD be at right angles to the same plane: AB shall he parallel to CD. Let them meet the plane at the points B, D ; join BD ; and in the plane draw DE... | |
 | Woolwich roy. military acad, Walter Ferrier Austin - 1880 - 190 pages
...the sides and angles of the quadrilateral ACBD formed by joining the extremities of the chords. 1 . If two straight lines be at right angles to the same plane, they shall be parallel to one another. 2. If two straight lines be cut by parallel planes, they shall be cut in the same ratio. 3. If two... | |
 | Education, Higher - 1883 - 536 pages
...outside. 13. Triangles and parallelograms of the same altitude are to one another as their bases. 14. If two straight lines be at right angles to the same plane, they shall be parallel to one another. 15. If the diagonals of a parallelogram are equal, all its angles are equal. 16. Show that the diagonals... | |
 | Euclid, Isaac Todhunter - Euclid's Elements - 1883 - 428 pages
...lines BC, BD, BE are in one and the same plane. PEOPOSITIOK 6. THEORZlf. fftico straight lines lie at right angles to the same plane, they shall be parallel to one another. Let the straight lines AS, CD he at right angles to the same plane : AB shall be parallel to CD. Let them meet the plane at... | |
 | E. J. Brooksmith - Mathematics - 1889 - 356 pages
...to accuracy in results. Full marks may be obtained by doing about three-quarters of this paper.] 1. If two straight lines be at right angles to the same plane they shall be parallel to one another. Only one line can be drawn from a given point perpendicular to a given plane, and it is the shortest... | |
 | Euclid - Geometry - 1892 - 460 pages
...is, BC, BD, BE are in one plane. QED PROPOSITION 6. THEOREM. If two straight lines are perpendicular to the same plane, they shall be parallel to one another. Let the st. lines AB, CD be perp. to the plane XY : then shall AB and CD be par1.* Let AB and CD meet the plane... | |
 | Euclid - Euclid's Elements - 1904 - 488 pages
...in one plane. 426 EUCLID-S ELEMENTS. PROPOSITION 6. THEOREM. If two straight lines are perpendicular to the same plane, they shall be parallel to one another. Let the st. lines AB, CD be perp. to the plane XY. Then shall AB and CD be par1.* Let AB and CD meet the plane... | |
 | Mathematics - 1871 - 280 pages
...the plane in which are DB, DC. Therefore AD is at right angles to the plane in which are DB,DC. II. If two straight lines be at right angles to the same plane, they shall be parallel to one another. B2 Let the straight lines AB, CD (fig. 4) be at right angles to the same plane ; then AB shall be parallel... | |
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If two straight lines be at right angles to the same plane, they shall be parallel to one another. Let the straight lines AB, CD be at right angles to the same plane : AB is parallel to CD. 
