Books Books
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.
Elements of Geometry: With Practical Applications to Mensuration - Page 170
by Benjamin Greenleaf - 1868 - 320 pages

## A Textbook on Sheet-metal Pattern Drafting, Volume 1

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...

## Woolwich Mathematical Papers for Admission Into the Royal Military Academy ...

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...

## Elementary Geometry, Plane and Solid: For Use in High Schools and Academies

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...

## Plane and Solid Geometry

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...

## Plane and Solid Geometry

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...

## Plane and Solid Geometry

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...

## Plane and Solid Geometry

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...

## Solid Geometry, Volumes 6-9

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...