 | Pierre Simon marquis de Laplace, Thomas Young - Capillarity - 1821 - 402 pages
...and, the radius being unity, 1°=:.01 7453293, 1'=.000290888, and 1"=: .000004848. 145. DEFINITION. A straight line is perpendicular to a plane, when it is perpendicular to every straight line meeting it in that plane. 146. DEFINITION. A plane is perpendicular to a plane,... | |
 | Adrien Marie Legendre - Geometry - 1822 - 394 pages
...height or thickness. VI. A plane is a surface, in which, if two points be assumed at will, and connected by a straight line, that line will lie wholly in the surface. VII. Every surface, which is not plane, or composed of plane surfaces, is a curve surface. VIII. A... | |
 | Adrien Marie Legendre, John Farrar - Geometry - 1825 - 280 pages
...polygon of the same perimeter. PART SECOND. SECTION FIRST. Of Planes and Solid Angles, DEFINITIONS. 313. A STRAIGHT line is perpendicular to a plane, when it is perpendicular to every straight line in the plane which passes through the foot of the perpendicular (326). Reciprocally,... | |
 | Adrien Marie Legendre, John Farrar - Geometry - 1825 - 294 pages
...polygon of the same perimeter. PART SECOND. SECTION FIRST. Of Planes and Solid Jingles. DEFINITIONS. 313. A STRAIGHT line is perpendicular to a plane, when it is perpendicular to every straight line in the plane which passes through the foot of the perpendicular (326). Reciprocally,... | |
 | Adrien Marie Legendre - 1825 - 570 pages
...polygon of the same perimeter. PART SECOND. SECTION FIRST. Of Planes and Solid Angler. DEFUflTIOJfS. 313. A STRAIGHT line is perpendicular to a plane, when it is perpendicular to every\straight line in the plane which passes through the foot of the perpendicular (326). Reciprocally,... | |
 | Timothy Walker - Geometry - 1829 - 138 pages
...the plane in every direction. This being admitted, we can demonstrate the following proposition — A straight line is perpendicular to a plane when it is perpendicular to two straight lines drawn through its foot in that plane — . Let the plane be AC (fig. 85) and suppose... | |
 | John Playfair - Geometry - 1829 - 210 pages
...BOOK VI. ELEMENTS OF GEOMETRY. BOOK XI. OF THE INTERSECTION OF PLANES. DEFINITIONS.— See Notes. 1. A straight line is perpendicular to a plane, when it is perpendicular to every straight line meeting it in that plane. 2. A plane is perpendicular to a plane, when all the... | |
 | Adrien Marie Legendre - Geometry - 1836 - 394 pages
...or thickness. 6. A plane is a surface, in which, if two points be assumed at pleasure, and connected by a straight line, that line ~will lie wholly in the surface. 7.. Every surface,-which is not a plane surface, or composed of plane surfaces, is a curved surface.... | |
 | Charles Davies - Geometry, Analytic - 1836 - 370 pages
...equation of a plane. A plane is a surface, in which, if two points be assumed at pleasure, and connected by a straight line, that line will lie wholly in the surface (Geom. Bk. I, Def. 6), If then, it be proved that this property belongs to the geometrical magnitude... | |
 | Charles Davies - Geometry, Analytic - 1838 - 366 pages
...equation of a plane. A plane is a surface, in which, if two points be assumed at pleasure, and connected by a straight line, that line will lie wholly in the surface (Geom. Bk. I, Def. 6). If then, it be proved that this property belongs to the geometrical magnitude... | |
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Conversely, the plane, in the same case, is perpendicular to the line. The foot of the perpendicular is the point in which it meets the plane. 
