 | Robert Simson - Trigonometry - 1806 - 548 pages
...planes AB, BC cannot but be a straight 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... | |
 | John Playfair - Mathematics - 1806 - 320 pages
...is the common section of these planes. 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... | |
 | John Mason Good - 1813 - 714 pages
...III. Theor. If two planes cut one another, 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... | |
 | Euclides - 1814 - 560 pages
...AB, N BC, cannot but be a straight line. Wherefore, if two planes, &c. QED PROP. IV. THEOR. SeeN. IP 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,... | |
 | Euclides - 1816 - 592 pages
...planes AB, BC, cannot but be a straight line. Wherefore, if two planes, &c. QED PROP. IV. THEOR. SeeN. 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... | |
 | John Playfair - Circle-squaring - 1819 - 348 pages
...planes AB and BC, or it is the common 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... | |
 | Mathematics - 1821 - 464 pages
...yards cost £2%, find the value of 5-f 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 intersection, it will be at right angles to the plane that passes through them.... | |
 | Robert Simson - Trigonometry - 1827 - 546 pages
...AB, BC, cannot but be a straight line. 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... | |
 | Pierce Morton - Geometry - 1830 - 584 pages
...and perpendicular itraight line. A straight line when said to be perpendicular to a plane . . 125 (a) If a straight line stand at right angles to each of two otlter straight lines at their point of intersection, it shall be at right angles to the plane in which... | |
 | Euclid - 1835 - 540 pages
...BC, cannot but be a straight line. 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... | |
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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. 
