 | Euclid, Isaac Todhunter - 1867 - عدد الصفحات: 424
...to EB as CF is to FD. [V. 11. Wherefore, if two straight lines &c. QED • PROPOSITION 18. THEOREM. If a, straight line be at right angles to a plane, every plane which passes through it shall be at right angles to that plane. Let the straight line AB be at right... | |
 | Gerardus Beekman Docharty - 1867 - عدد الصفحات: 474
...parallel ; .-.AG: GD::CF:FD. /. comparing this with the first proportion, AE: EB;:CF:FD. PROPOSITION XV. If a straight line be at right angles to a plane, every plane which passes through it will be at right angles to that plane. Let the straight line PQ be at right... | |
 | Euclid, Isaac Todhunter - 1867 - عدد الصفحات: 426
...is to EB as CF is to FD. [V. 11. Wherefore, if two straight lines &c. QED PROPOSITION 18. THEOREM. If a straight line be at right angles to a plane, every plane which passes through it shall be at right angles to that plane. Let the straight line AB be at right... | |
 | Robert Potts - 1868 - عدد الصفحات: 434
...EB, so is CF to JPD. (v. 11.) Wherefore, if two straight lines, &c. QED PROPOSITION XVIII. THEOREM. If a straight line be at right angles to a plane, every plane which passe* through it shall be at right angles to that plane. Let the straight line AB be at right... | |
 | Edinburgh univ - 1871 - عدد الصفحات: 392
...the equations— 102 14. Prove the rule for finding the greatest common measure of two numbers. 15. If a straight line be at right angles to a plane, every plane which passes through it is at right angles to the plane. 1 6. Given two sides of a triangle and the... | |
 | Euclides, James Hamblin Smith - 1872 - عدد الصفحات: 376
...is to XD as CF is to .FD. Hence AE istoEBasCFis to .FIX VI. 2. V. 5. QED PROPOSITION XVIII. THEOREM. If a straight line be at right angles to a plane, every plane, which passes through it, must be at right angles to that plane. Let the st. line AB be _L to the plane... | |
 | Euclides - 1874 - عدد الصفحات: 342
...EB, so is CF to FD (V. 11). Wherefore, if two straight lines, &c, QED PROPOSITION 18. — Theorem. If a straight line be at right angles to a plane, every plane which passes through it is at right angles to that plane. Let the straight line AB be at right angles... | |
 | George Henry Lewes - 1875 - عدد الصفحات: 500
...the essence of Eeasoning. Take for example the demonstration of Euclid (XI. 18) of the proposition, " If a straight line be at right angles to a plane, every plane which passes through it shall be at right angles to that plane." This is not Reasoning at all, according... | |
 | Isaac Sharpless - 1879 - عدد الصفحات: 282
...is parallel to AC, (V. 2), AX:XD:: CF: FD; .-.(TV.15},AE:EB:: CF: FD. Proposition 17. Tlieorem.—If a straight line be at right angles to a plane, every plane which passes through that line is at right angles to the first-mentioned plane. Let the straight line... | |
 | Woolwich roy. military acad, Walter Ferrier Austin - 1880 - عدد الصفحات: 190
...00, are cut by parallel planes in ABC, A'B'C', show that the triangles ABC, A'B'O' are similar. 3. If a straight line be at right angles to a plane, every plane which passes through it shall be at right angles to that plane. When is it possible to draw through... | |
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Let any plane DE pass through AB, and let CE be the common section of the planes DE... 
