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If two planes are perpendicular to 'each other, a straight line drawn in one of them, perpendicular to their intersection, will be perpendicular to the other.
Elements of Geometry and Trigonometry: From the Works of A.M. Legendre - Page 172
by Adrien Marie Legendre - 1874 - 455 pages

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

Thomas Franklin Holgate - Geometry - 1901 - 462 pages
...from any point of their intersection, perpendicular to one plane, must lie in the other. § 440. (5) If two planes are perpendicular to each other, a straight line drawn from any point in one of them, perpendicular to the other, must lie in the first plane. § 442. (6)...

## University of the State of New York Bulletin

Education - 1902 - 880 pages
...prisnl) tetraedron, directrix, great circle, polar triangles, spheric excess of a triangle. 2 Prove that if two planes are perpendicular to each other, a straight...in one of them perpendicular to their intersection is perpendicular to the other plane. 3 Complete and demonstrate the following: the lateral area •of...

## Bulletin

Education - 1902 - 780 pages
...prjsni) tetraedron, directrix, great circle, polar triangles, spheric excess of a triangle. 2 Prove that if two planes are perpendicular to each other, a straight...in one of them perpendicular to their intersection is perpendicular to the other plane. 3 Complete and demonstrate the following : the lateral area of...

## Solid Geometry, Volumes 6-9

George Albert Wentworth - Geometry, Solid - 1902 - 248 pages
...these variables are equal. § 284 A'-B'C'-D' Z A'B'D' ' l: " Z.ABD PROPOSITION XVIII. THEOREM. 551. If two planes are perpendicular to each other, a straight...in one of them perpendicular to their intersection is perpendicular to the other plane. Let the plane PQ be perpendicular to MN, and let CD be drawn in...

## Plane and Solid Geometry

George Albert Wentworth - Geometry - 1904 - 496 pages
...A'-B'C'-D' Z A'B'D' < A-BC-D ~ Z.ABD OED BOOK VI. SOLID GEOMETRY. PROPOSITION XVIII. THEOREM. 551. If two planes are perpendicular to each other, a straight...in one of them perpendicular to their intersection is perpendicular to the other plane. Let the plane PQ be perpendicular to MN, and let CD be drawn in...

## Solid Geometry

Fletcher Durell - Geometry, Solid - 1904 - 232 pages
...right Z , (for AB _L -IfJVfcy hyp.). :. PQ ± MN. Art. 547. QED PROPOSITION XVIII. THEOREM 557. // two planes are perpendicular to each other, a straight line drawn in one of them perpendicular to their line of intersection is perpendicular to the other plane. Given the plane PQ J. plane MN and intersecting...

## School Science and Mathematics, Volume 12

Education - 1912 - 942 pages
...perpendicular planes a line be drawn perpendicular to their intersection, it is perpendicular to the other. If two planes are perpendicular to each other, a straight line drawn from any point in one, perpendicular to the other, lies in the first. If two planes are perpendicular...

## Treatise on Elementary Geometry

William Chauvenet - 1905 - 336 pages
...the two straight lines BQ, BC, is perpendicular to their plane MN (Proposition IV.). 37. COKOLLAKY I. If two planes are perpendicular to each other, a straight line drawn through any point of their intersection perpendicular to one of the planes will lie in the other, (v....