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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.
Plane and Solid Geometry: To which is Added Plane and Spherical Trigonometry ... - Page 139
by George Roberts Perkins - 1856 - 235 pages

## Syllabus of Geometry

George Albert Wentworth - Mathematics - 1896 - 68 pages
...their intersection is a straight line. 472. 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. 473. Every perpendicular that can be drawn to a straight line at a given point lies...

## Elements of Geometry

Andrew Wheeler Phillips, Irving Fisher - Geometry - 1897 - 374 pages
...through its foot. In the same case the plane is perpendicular to the line. PROPOSITION III. THEOREM 511. If a straight line is perpendicular to each of two...intersection, it is perpendicular to the plane of those lines. GIVEN—the Straight line BG perpendicular to each of the two intersecting straight lines...

## Elements of Geometry

Andrew Wheeler Phillips, Irving Fisher - Geometry - 1897 - 376 pages
...through its foot. In the same case the plane is perpendicular to the line. PROPOSITION III. THEOREM 511. If a straight line is perpendicular to each of two...their point of intersection, it is perpendicular to Hie plane of those lines. GIVEN — the straight line BG perpendicular to each of the two intersecting...

## Entrance Examinations in Mathematics, 1884 to 1898 [with Supplements to 1900]

Yale University - 1898 - 212 pages
...a polyhedron, a tetrahedron, a prism, a parallelepiped, a pyramid, a cone, a cylinder, a sphere. 2. If a straight line is perpendicular to each of two...intersection, it is perpendicular to the plane of those lines. 3. If a pyramid is cut by a plane parallel to its base, (a) the edges and altitude are...

## Yale University Entrance Examinations in Mathematics: 1884 to 1898

Mathematics - 1898 - 228 pages
...a polyhedron, a tetrahedron, a prism, a parallelopiped, a pyramid, a cone, a cylinder, a sphere. 2. If a straight line is perpendicular to each of two...intersection, it is perpendicular to the plane of those lines. 3. If a pyramid is cut by a plane parallel to its base, (a) the edges and altitude are...

## Plane and Solid Geometry

James Howard Gore - Geometry - 1898 - 232 pages
...the plane at the greater distance from the foot of the perpendicular. PROPOSITION III. THEOREM. 337. If a straight line is perpendicular to each of two...of intersection it is perpendicular to the plane of those lines. To prove that BA is perpendicular to EA and hence perpendicular to MN. Make AC equal to...

## Examinations Papers

1898 - 872 pages
...cut two parallel straight lines in A, B, C and P, Q, R respectively, prove that AS : BC- PQ : QB. 4. If a straight line is perpendicular to each of two...point of intersection it is perpendicular to the plane in which they lie. Find the locus of a point equidistant from three given points. II. 1. Shew how to...

## Plane and Solid Geometry

William James Milne - Geometry - 1899 - 396 pages
...direction with reference to the plane? Theorem. 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. Data : Any two straight lines, as AB and CD, intersecting at E; MN, the plane of these...