 | Horatio Nelson Robinson - Geometry - 1860 - 470 pages
...— The truth of this proposition is implicitly assumed in the definitions of this Book. THEOREM III. If a straight line stand at right angles to each of two other straight lines at their point of intersection, it will be at right angles to the plane of those... | |
 | Benjamin Greenleaf - Geometry - 1862 - 532 pages
...planes AB, CD is a straight line. PROPOSITION IV. — THEOREM. 401. If a straight line is perpendicular to each of two straight lines, at their point of intersection, it is perpendicular to the plane in which the two lines lie. Let the straight line AB be perpendicular... | |
 | Benjamin Greenleaf - Geometry - 1862 - 518 pages
...planes AB, CD is a straight line. PROPOSITION IV. — THEOREM. 401. If a straight line is perpendicular to each of two straight lines, at their point of intersection, it is perpendicular to the plane in which the two lines lie. Let the straight line AB be perpendicular... | |
 | Benjamin Greenleaf - Geometry - 1863 - 504 pages
...AB, CD is a straight line. B 1> PROPOSITION IV. — THEOREM. 401. If a straight line is pcrpemlicular to each of two straight lines, at their point of intersection, it is perpendicular to the plane in which the two lines lie. Let the straight line AB be perpendicular... | |
 | Euclides - 1864 - 448 pages
...and AFis perpendicular to DE; therefore AFis perpendicular to each of the straight lines GH, DE. But if a straight line stand at right angles to each of two straight lines in the point of their intersection, it is also at right angles to the plane passing through them :... | |
 | Robert Potts - 1865 - 528 pages
...and AFis perpendicular to DE; therefore AFis perpendicular to each of the straight lines GH, DE. But if a straight line stand at right angles to each of two straight lines in the point of their intersection, it is also at right angles to the plane passing through them :... | |
 | Euclides - 1865 - 402 pages
...plane can he drawn through three points which are not on the same right line * . . . . . XI. 2. 3. If a straight line stand at right angles to each of two straight lines in the point of their intersection, it is also at right angles to the plane through them, that is,... | |
 | James Robert Christie - Mathematics - 1866 - 428 pages
...internally, any straight line drawn through the point of contact will cut off similar segments. 4. If a straight line stand at right angles to each of...straight lines at their point of intersection, it shall also be at right angles to the plane which passes through them, that is, to the plane in which... | |
 | Euclid, Isaac Todhunter - Euclid's Elements - 1867 - 424 pages
...AB and BC cannot but be a straight line. Wherefore, if t wo planes &c. QED PROPOSITION 4. THEOREM. If a straight line stand at right angles to each of two straight lines at the point of their intersection, it shall also be at right angles to the plane which passes through... | |
 | Euclid, Isaac Todhunter - Euclid's Elements - 1867 - 426 pages
...planes AB and EC cannot but be a straight line. Wherefore, if two planes &c. QED PROPOSITION 4. THEOREM. If a straight line stand at right angles to each of two straight lines at the -point of their intersection, it shall also lie at right angles to the plane which passes through... | |
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If a straight line stand at right angles to each of two straight lines at the point of their intersection, it shall also be at right angles to the plane which passes through them, that is, to the plane in which they are. 
