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 ## Proceedings of the High School Conference of ...

High schools - 1919 - 962 pages
...subject, namely a model to illustrate the theorem: If a line is perpendicular to each of two other lines at their point of intersection it is perpendicular to the plane of the two lines. This model is made according to specifications, insuring uniformity, and I make a... ## Solid Geometry, with Problems and Applications

Herbert Ellsworth Slaught, Nels Johann Lennes - Geometry, Solid - 1919 - 240 pages
...PERPENDICULAR TO THE PLANE OF TWO GIVEN LINES 76. THEOREM III. If a line is perpendicular to each of two lines at their point of intersection, it is perpendicular to the plane of these lines. Given a line / perpendicular to each of the lines /, and /2 at the point P. To prove... ## Bulletin, Issues 25-53

United States. Office of Education - 1921 - 1268 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... ## A History of Greek Mathematics, Volume 2

Sir Thomas Little Heath - Mathematics - 1921 - 612 pages
...(1) that the ‘distance' between the two lines as defined is perpendicular to both, and (2) that, if a straight line is perpendicular to each of two straight lines and meets both, the two straight lines are parallel, and the ‘distance' is the intercept on the perpendicular... ## Bulletin

Education - 1921 - 1198 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... ## Solid Geometry

Charles Austin Hobbs - Geometry, Solid - 1921 - 216 pages
...produced indefinitely. Proposition 204 Theorem // a line is perpendicular to each of two intersecting lines at their point of intersection, it is perpendicular to the plane determined by these lines. Hypothesis. The line AB is -L to the lines BC and BD at their point of intersection,... ## The Reorganization of Mathematics in Secondary Education

National Committee on Mathematical Requirements - Mathematics - 1922 - 84 pages
...meet, they intersect in a straight line. 2. If a }ine 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... ## General Mathematics, Book 2

Raleigh Schorling, William David Reeve - Mathematics - 1922 - 460 pages
...dihedral angle. 3. By definition of a perpendicular. 4. Given. 5. If a line is perpendicular to two lines at their point of intersection, it is perpendicular to the plane determined by them. 282. Corollary 1. If two planes are perpendicular to each other, a, perpendicular... ## Schultze and Sevenoak's Plane and Solid Geometry; Revised by Arthur Schultze

Arthur Schultze, Frank Louis Sevenoak - Geometry - 1913 - 484 pages
...foot in the plane. PROPOSITION VIII. THEOREM 499. 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. A A Given BC and BD _L AB, and plane MN containing BC and BD. To prove AB _L plane... 