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

## Essentials of Solid Geometry

David Eugene Smith - Geometry, Solid - 1924 - 256 pages
...Proposition 2. Perpendicular to a Plane 37. Theorem. If a line is perpendicular to each of two intersecting lines at their point of intersection, it is perpendicular to the plane of the two lines. Given AO _L to OP and OR at O, and m, the plane of OP and OR. Prove that AO is _L...

## Questions Set at the Examinations ...

College Entrance Examination Board - Universities and colleges - 1924 - 126 pages
...Omit one question. Take ic = 3. 14. 1. Prove: If a line is perpendicular to each of two intersecting lines at their point of intersection, it is perpendicular to the plane of the two lines. 2. Prove: In a circular cone a section made by a plane parallel to the base is a...

## Mathematics: Course of Study for Senior and Junior High Schools

Baltimore (Md.). Department of Education - Mathematics - 1924 - 182 pages
...meet, they intersect in a straight line. 2 . If a line is perpendicular to each of two intersecting lines at their point of intersection, it is perpendicular to the plane of the two lines. 3 . Every perpendicular to a given line at a given point lies in a plane perpendicular...

## The Reorganization of Mathematics in Secondary Education (part I): A ..., Part 1

National Committee on Mathematical Requirements - Mathematics - 1927 - 208 pages
...they intersect in a straight line, [1, cd] 2. If a line is perpendicular to each of two intersecting lines at their point of intersection it is perpendicular to the plane of the two lines. [2*, cd*] 3. Every perpendicular to a given line at a given point lies in a plane...

## Geometry - Plane, Solid and Analytic Problem Solver

Research & Education Association Editors, Ernest Woodward - Mathematics - 2012 - 1080 pages
...point P (L2) . Now, L _L L. at P and L _L L2 at P. But, if a line is perpendicular to 2 intersecting lines at their point of intersection, it is perpendicular to the plane containing the 2 lines. Hence, L is perpendicular to the plane containing L^ and L2 at the point P....

## The New Zealand University Calendar, Volume 32

University of New Zealand - 1904 - 360 pages
...straight line. Through three points not collinear only one plane can be drawn. If a straight line be perpendicular to each of two straight lines at their...point of intersection it is perpendicular to the plane passing through them. All normals to the same plane are parallel to one another. The projection of...

## Calendar

University of St. Andrews - 1900 - 670 pages
...equal to OQ ; show that BP is equal to CQ. 12. Prove that, if a straight line stand at right angles to each of two straight lines at their point of intersection, it is at right angles to the plane which passes through them — that is, to the plane in which they are....

## The Bombay University Calendar

University of Bombay - 1903 - 1170 pages
...CONIC SECTIONS. 1. If a straight line be perpendicular to each of two intersecting straight 10 liues at their point of intersection, it is perpendicular to the plane in which they are. If perpendiculars to two faces of a tetrahedron from opposite vertices intersect, prove that...