 | Elias Loomis - Conic sections - 1849 - 252 pages
...common section of the first two planes; then will AB be perpendicular to the plane MN. PROPOSITION IX. THEOREM. Two straight lines which are perpendicular to the same plane, are parallel to each other. In the plane MN, draw the straight line BD joining the points B and D. Through the lines AB, BD pass... | |
 | Charles Astor Bristed - 1852 - 470 pages
..."Why are we bound to practise virtue ?" EUCLID. BOOK XI. TRINITY COLLEGE. FRIDAY, May 2*7, 1842. 2. Two straight lines which are perpendicular to the same plane are parallel to one another. 3. Draw a straight line perpendicular to a plane from a given point without it. 4. If... | |
 | Elias Loomis - Conic sections - 1857 - 242 pages
...in the plane AE ; hence it is their common section AB. Therefore, if two planes, &c. PROPOSITION IX. THEOREM. Two straight lines which are perpendicular to the same plane, are > -^r^Jel to each other. Let the two stu''srht lines AB,-CD be each of them perpendicular to the same... | |
 | Elias Loomis - Conic sections - 1858 - 256 pages
...in the plane AE ; hence it is their common section AB. Therefore, if two planes, &c. PROPOSITION IX. THEOREM. Two straight lines which are perpendicular to the same plane, are r^ralkl to each other. Let the two stu ;ght lines AB, CD be each of them perpendicular to the same... | |
 | Elias Loomis - Conic sections - 1877 - 458 pages
...piano AE ; hence it is their common section AB. Therefore, if two planes, etc. PROPOSITION IX. THKOUKM. Two straight lines which are perpendicular to the same plane are parallel to each other. Let the two straight lines AB, CD be each of them perpendicular to the same plane MN ; then will AB... | |
 | Alfred Hiley - 1879 - 228 pages
...everywhere equally distant from each other. Thus the floor and ceiling of a room are parallel planes. 4. Straight lines which are perpendicular to the same...plane are parallel to each other ; and two parallel straight lines comprised between two parallel planes are equal. 5. The different solids have been so... | |
 | Elias Loomis - Conic sections - 1880 - 452 pages
...in the plane AE; hence it is their common section AB. Therefore, if two planes, etc. PROPOSITION IX. THEOREM. Two straight lines which are perpendicular to the same plane are parallel to each other. Let the two straight lines AB, CD be each of them perpendicular to the same plane MN ; then will AB... | |
 | Great Britain. Education Department. Department of Science and Art - 1882 - 510 pages
...to a given line. 4. Prove that (1) two planes which are perpendicular to the same line, and (2) two lines which are perpendicular to the same plane, are parallel to each other. 5. Given a plane, and a point A without it, find another point B, so that every point in the plane... | |
 | George Washington Hull - Geometry - 1897 - 408 pages
...at their point of intersection, and is therefore perpendicular to MN. § 380. QED 387. COR. 1.—Two lines which are perpendicular to the same plane are parallel to each other. Given—AB and CD perpendicular to the plane MN. To Prove—AB and CD parallel. Dem. —If AB and CD... | |
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CD be each of them perpendicular to the same plane MN ; then will AB be parallel to CD. In the plane MN, draw the straight line BD, joining the points B and D. Through the lines AB, BD pass the plane EF ; it will be perpendicular to the plane MN (Pr. 