 | Adrien Marie Legendre - Geometry - 1874 - 512 pages
...straight line ; which was to be proved. PROPOSITION IV. THEOREM. Jf a straight line is perpendicular to two straight lines at their point of intersection, it is perpendicular to the plane of those lines. Let JOT be the plane of the two lines BB, (7(7, and let AP be perpendicular to these... | |
 | Francis Cuthbertson - Euclid's Elements - 1874 - 400 pages
...DEFINITION. A straight line is said to be perpendicular to a plane PROPOSITION VI. . If a straight line be perpendicular to each of two straight lines at their point of intersection, it shall be perpendicular to the plane passing through them. Let PQ be j . to QA and QC. Then shall PQ... | |
 | William Chauvenet - Geometry - 1875 - 468 pages
...will be the required perpendicular. PROPOSITION V.—THEOREM. 13. If a etraight line isperpendicular to each of two straight lines at their point of intersection., it is perpendicular to the plane of Uiose lines. Let AP be perpendicular to PR and PC, at their intersection P; then, AP is perpendicular... | |
 | William Chauvenet - Geometry - 1875 - 390 pages
...these points; the straight line AP will be the required perpendicular. PROPOSITION V.— THEOREM. ^ 13. If a straight line is perpendicular to each of two straight lines at thttir point of intersection, it is perpendicular to the plane of those lines. Let AP be perpendicular... | |
 | 1876 - 646 pages
...area will be a maximum when these sides are at right angles. II.— SOLID AND SPHERICAL GEOMETRY. 7. If a straight line is perpendicular to each of two...of intersection, it is perpendicular to the plane of these lines. 8. Define symmetrical polyhedral angles. Illustrate the definition by a figure. 9.... | |
 | William Guy Peck - Conic sections - 1876 - 394 pages
...a plane. PROPOSITION III. THEOREM. If a straight line is perpendicular to each of two intersecting lines at their point of intersection, it is perpendicular to the plane of those lines. Let AQ and DQ be two lines in the plane KL, and let PQ be perpendicular to both ; then... | |
 | Elias Loomis - Geometry - 1877 - 458 pages
...is their common section. Hence, if two planes, etc. PROPOSITION IV. THEOREM. If a straight line be perpendicular to each of two straight lines at their point of intersection, it will be perpendicular to the plane in which these lines are. Let the straight line AB be perpendicular... | |
 | J. B. Millar - Geometry, Descriptive - 1878 - 264 pages
...planes out one another, their common section is a straight line 2 Theorem III. If a straight line be perpendicular to each of two straight lines at their point of intersection, it shall also be perpendicular to their plane 3 Theorem IV. Every plane which contains the normal to another... | |
 | Isaac Sharpless - Geometry - 1879 - 282 pages
...is therefore their common section. Proposition 4. Theorem.—If a straight line be at right angles to each of two straight lines at their point of intersection, it is at right angles to the plane in which these straight lines are. Let AB be at right angles to each of... | |
 | Cornell University - 1880 - 868 pages
...symmetrical triedral angles, a segment of a sphere, the axis of a parabola. 2. If a straight line be perpendicular to each of two straight lines at their...of intersection, it is perpendicular to the plane of those lines. 3. Two prisms are equal, if three faces including a triedral angle of one be respectively... | |
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If a straight line is perpendicular to each of two straight lines at their point of intersection, it is perpendicular to the plane of those lines. 
