Books Books 1 - 10 of 32 on AF is perpendicular to each of the straight lines GH, DE. But if a straight line.... 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. New Cambridge Guide; Or, A Description of the University, Town, and County ... - Page 174
1804 - 130 pages ## Elements of Geometry: Containing the First Six Books of Euclid, with a ...

John Playfair - 1806 - 311 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... ## The Elements of Euclid: Viz. the First Six Books, Together with the Eleventh ...

Euclid, Robert Simson - 1806 - 518 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... ## Pantologia. A new (cabinet) cyclopædia, by J.M. Good, O. Gregory ..., Volume 5

John Mason Good - 1813
...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... ## The Elements of Euclid: Viz. the First Six Books, Together with the Eleventh ...

Euclides - 1816 - 528 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,... ## Elements of Geometry: Containing the First Six Books of Euclid, with a ...

John Playfair - 1819 - 333 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... ## Elements of Geometry: Containing the First Six Books of Euclid: With a ...

John Playfair - 1819 - 317 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... ## Cambridge Problems: Being a Collection of the Printed Questions Proposed to ...

1821 - 425 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,... ## A Popular Course of Pure and Mixed Mathematics ...: With Tables of ...

Peter Nicholson - 1825 - 372 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,... ## The Elements of Euclid: The Errors by which Theon, Or Others, Have Long ...

Robert Simson - 1827 - 513 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... 