 | John Playfair - Mathematics - 1806 - 320 pages
...Therefore, if two planes, &c. QED A PROP. IV. THEOR. a 2. 6. IF a straight line stand at right angles to each of two 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 at right... | |
 | Robert Simson - Trigonometry - 1806 - 546 pages
...line. Wherefore, if two planes, &c. QED PROP. IV. THEOR. SeeN. IF a straight line stand at right angles to each of two straight lines in the point of their intersection, it shall also be at ri^ht angles to the plane which passes through them, that is, to the plane in which... | |
 | John Mason Good - 1813 - 714 pages
...their common section is a straight line. Piop. IV. Theor. If a straight line stand at right angles to each of two straight lines in 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... | |
 | Euclides - 1816 - 588 pages
...ThereforeAFis 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 shall also be at right angles to the plane passing through them. But the plane passing through ED,... | |
 | John Playfair - Circle-squaring - 1819 - 350 pages
...section of these planes. Therefore, &c. Q,. ED PROP. IV. THEOR. If a straight line stand at right angles to each of two 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 at right... | |
 | John Playfair - 1819 - 354 pages
...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. Sob.). And the plane passing through... | |
 | Mathematics - 1821 - 464 pages
...yards lx>th by vulgar fractions and by decimals. 2. Prove that if a straight line stand at right angles to each of two straight lines in the point of their...that the diagonals of a rhombus bisect each other at right angles. 4. If (a) be the first term, and (i) the sum of three terms of a geometric progression,... | |
 | Peter Nicholson - Mathematics - 1825 - 1046 pages
...if perpendicular to each of the straight lines GH, DE. But if a straight line stands at right anglei to each of two straight lines in the point of their intersection, it shall also be at right angles to the plane passing through them. But the plane passing through ED,... | |
 | Robert Simson - Trigonometry - 1827 - 546 pages
...Wherefore, if two planes, &c. Q. E, D. PROP. IV. THEOR. See N. If a straight line stand at right angles to each of two straight lines in 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... | |
 | Euclid - 1835 - 540 pages
...Wherefore, " if two planes" &c. QED L. 'A PROP. IV. THEOR. See N. If a straight line stand at right angles to each of two straight lines in the point of their intersection, if shall also be at right angles to the plane which passes through them, that is, to the plane in which... | |
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AF is 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 : (xi. 
