| International Correspondence Schools - Sheet-metal work - 1901 - 570 pages
...PR is a right angle, it can be proved that O PS is also a right angle. Hence, a straight line that **is perpendicular to each of two straight lines at their point of intersection** is perpendicular to t he plane containing those lines. 11. Two planes that can never meet, no matter... | |
| Eldred John Brooksmith - Mathematics - 1901 - 368 pages
...spire being at the same level, determine the height of the spire. 7. Prove that a straight line which **is perpendicular to each of two straight lines at their point of intersection** is perpendicular to the plane containing them. 8. Prove that, if each of the edges of a tetrahedron... | |
| Thomas Franklin Holgate - Geometry - 1901 - 462 pages
...LINES AND PLANES IN SPACE PROPOSITION IV 397. If a straight line is perpendicular to each of two given **straight lines at their point of intersection, it is perpendicular to the plane** of those lines. Let the straight line AO be perpendicular to both the straight lines BO and CO at their... | |
| Arthur Schultze, Frank Louis Sevenoak - Geometry - 1901 - 394 pages
...they may be produced. PROPOSITION II. THEOREM 461. If a straight line is perpendicular to each of two **lines at their point of intersection, it is perpendicular to the plane** of those lines. Hyp. AB is _L to BC and BD at B. To prove AB is J_ to the plane MN containing BC and... | |
| Arthur Schultze, Frank Louis Sevenoak - Geometry - 1901 - 396 pages
...they may be produced. PROPOSITION II. THEOREM 461. If a straight line is perpendicular to each of two **lines at their point of intersection, it is perpendicular to the plane** of those lines. Hyp. AB is J. to BC and BD at B. To prove AB is J. to the plane MN containing BC and... | |
| Arthur Schultze, Frank Louis Sevenoak - Geometry - 1902 - 394 pages
...they may be produced. PROPOSITION II. THEOREM 461. If a straight line is perpendicular to each of two **lines at their point of intersection, it is perpendicular to the plane** of those lines. Hyp. AB is -l. to BC and BD at B. To prove AB is -l. to the plane MN containing BC... | |
| James Howard Gore - Geometry - 1902 - 266 pages
...the perpendicular. PROPOSITION III. THEOREM. 337. If a straight line is perpendicular to each of tivo **straight lines at their point of intersection it is perpendicular to the plane** of those lines. Let BA be perpendicular to AD and AC two intersecting lines in the plane MN, and let... | |
| George Albert Wentworth - Geometry, Solid - 1902 - 248 pages
...planes. § 50. r > PROPOSITION II. THEOREM. 507. If a straight line is perpendicular to each of two other **straight lines at their point of intersection, it is perpendicular to the plane** of the two lines. Let AB be perpendicular to BC and BD at B. To prove that AB is -L to the plane MN... | |
| University of St. Andrews - 1902 - 740 pages
...BC. AE cuts the diagonal BD in F. Prove that BF is £ BD. 11. If a straight line be at right angles **to each of two straight lines at their point of intersection it** shall be at right angles to the plane containing them. From a point P are drawn lines PA, PB perpendicular... | |
| Euclid - Euclid's Elements - 1904 - 488 pages
...the plane of AB, AC ; .-. DA is perp. to this plane. QED PROPOSITION 4. THEOREM. [Euclid-s Proof.] **If a straight line is perpendicular to each of two straight lines at their point of intersection, it** shall also be perpendicular to the plane in which they lie Let the st. line EF be perp. to each of... | |
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