 | Mathematics - 1836 - 488 pages
...are in one plane. III. If two planes cut one another, their common section is a straight line. IV. If a straight line stand at right angles to each of two straight lines in their point of intersection, it will also be at right angles to the plane in which these lines are.... | |
 | A. Bell - Conic sections - 1837 - 180 pages
...common to the planes AB and BC, or it is the common section of these planes. PROPOSITION IV. THEOREM. If a straight line stand at right angles to each of...straight lines in the point of their intersection, it will also be at right angles to the plane in which these lines are. Let PO be perpendicular to the... | |
 | John Playfair - Euclid's Elements - 1837 - 332 pages
...: Therefore AF is perpendicular to each of the straight lines GH, DE. But if a straight line stands 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 (4. 2. Sup.). And the plane passing through... | |
 | Robert Simson - Geometry - 1838 - 434 pages
...: therefore AF is perpendicular to each of the straight lines GH, DE. But if a straight line stands at right angles to each of two straight lines in the...intersection, it shall also be at right angles to the plane passing through them. But the plane passing through ED, GH is the plane BH ; therefore AF is perpendicular... | |
 | Euclides - Geometry - 1841 - 378 pages
...AF is perpendicular to DE; therefore AF is perpendicular to each of the straight lines GH, DE. But if a straight line stand at right angles to each of...straight lines in the point of their intersection, it is also at right angles* to the plane * 4. 11. passing through them: but the plane passing through... | |
 | Thomas Grainger Hall - Geometry, Descriptive - 1841 - 214 pages
...planes AB, B c, cannot but be a straight line. PROPOSITION IV. If a straight line be perpendicular to each of two straight lines in the point of their intersection, it shall also be perpendicular to the plane passing through them. Let a straight line AB, be -<- to two straight lines... | |
 | John Playfair - Euclid's Elements - 1842 - 332 pages
...therefore common to the planes AB and BC, or it is the common section of these planes. PROP. IV. THEOR. If a straight line stand at right angles to each of...straight lines in the point of their intersection, it will also be at right angles to the plane in which these lines are. Let the straight line AB stand... | |
 | Euclides - 1842 - 316 pages
...planes AB and BC, or it is the common section of these planes. Therefore, &c. QED PROP. IV. THEOR. IF a straight line stand at right angles to each of...straight lines in the point of their intersection: it will also be at right angles to the plane in which these lines are. Let the straight line EF stand... | |
 | Euclid - Geometry - 1845 - 218 pages
...AF is perpendicular to DE ; therefore AF is perpendicular to each of the straight lines GH, DE. But if a straight line stand at right angles to each of...lines in the point of their intersection, it shall * 4. 11. also be at right angles* to the plane passing through them: but the plane passing through... | |
 | Euclides - 1845 - 546 pages
...AF is perpendicular to DE ; therefore AF is perpendicular to each of the straight lines GH, DE. But if a straight line stand at right angles to each of...straight lines in the point of their intersection, it is also at right angles to the plane passing through them : (xi. 4.) but the plane passing 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. 
