 | Isaac Todhunter - 1880 - 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... | |
 | 1884 - عدد الصفحات: 538
...the base, the triangles on each side of it are similar to the whole triangle and to one another. 15. 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. 16. In the figure of Euclid IV. 10,... | |
 | Isaac Sharpless - 1882 - عدد الصفحات: 286
...is parallel to AC, (V. 2), AX:XD:: CF:FD; .-. (IV. 15), AE :EB::CF: FD. Proposition 17. Theorem. — 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... | |
 | E. J. Brooksmith - 1889 - عدد الصفحات: 356
...correctly about three-fourths of this paper. Great importance will be attached to accuracy. ~\ 1 . If a straight line be at right angles to a plane, every plane which passes through it shall be at right angles to the plane. If CD be at right angles to a plane... | |
 | Edward Mann Langley, W. Seys Phillips - 1890 - عدد الصفحات: 538
...perpendicularly to the common section of the planes are perpendicular to the other planes. PROP. 18.— If a straight line be at right angles to a plane, every plane which passes through that line shall be at right angles to that plane. Let the st. line AB be xr to... | |
 | New Brunswick. Board of Education, New Brunswick. Department of Education - 1893 - عدد الصفحات: 800
...can there not be more than five regular Polyhedra? •5. When is a plane perpendicular to a plane 1 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. A If two planes, which cut one another,... | |
 | New Brunswick. Board of Education, New Brunswick. Department of Education - 1893 - عدد الصفحات: 806
...can there not be more than five regular Polyhedra '? -5. When is a plane perpendicular to a plane ? 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. 6. If two planes, which cut one another,... | |
 | 1894 - عدد الصفحات: 832
...Why can there not be more than five regular Polyhedra 1 5. When is a plane perpendicular to a plane 1 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. "6. If two planes, which cut one another,... | |
 | Daniel Alexander Murray - 1906 - عدد الصفحات: 466
...equal. (See Euc. XI. 10.) Hence, theplane angle can be taken as the measure of the diedral angle. 2. a. If a straight line be at right angles to a plane, every plane which passes through the line is at right angles to that plane. (Euc. XL 18.) b. If two planes which... | |
 | Daniel Alexander Murray - 1908 - عدد الصفحات: 132
...equal. (See Euc. XI. 10.) Hence, the plane angle can be taken as the measure of the diedral angle. 2. a. If a straight line be at right angles to a plane, every plane which passes through the line is at right angles to that plane. (Euc. XI. 18.) 6. If two planes which... | |
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Let any plane DE pass through AB, and let CE be the common section of the planes DE... 
