Books Books A STRAIGHT line is perpendicular to a plane, when it is perpendicular to every straight line which it meets in that plane. A Course of Mathematics: In Two Volumes. For the Use of Academies, as Well ... - Page 306
by Charles Hutton - 1818 ## Elementary Geometry: With Applications in Mensuration

Charles Davies - Geometry - 1850 - 218 pages
...three to 120°x3r=360°0 GEOMETRY. BOOK V. OF PLANES AND THEIR ANGLES* DEFINITIONS. 1 . A straight line is perpendicular to a plane, when it is perpendicular to every straight line of the plane which it meets. The point at which the perpendicular meets the plane, is... ## Elements of Geometry and Trigonometry: With Applications in Mensuration

Charles Davies - Geometry - 1886 - 334 pages
...the three to 120° X 3= 360" GEOMETRY. BOOK V. OF PLANES AND THE1B ANGLES. DEF1N1T1ONS. 1. A straight line is perpendicular to a plane, when it is perpendicular to every straight line of the plane which it meets. The point at which the perpendicular meets the plane, is... ## Elements of Geometry and Trigonometry from the Works of A.M. Legendre ...

Charles Davies - Geometry - 1854 - 436 pages
...always be placed as in the f1gure. BOOK VI. PLANES AND POLYEDRAL ANGLES. DEFINITIONS. 1. A straight line is perpendicular to a plane, when it is perpendicular to every straight line of the plane which passes through its foot : conversely, the plane is perpendicular to... ## Mathematical Dictionary and Cyclopedia of Mathematical Science: Comprising ...

Charles Davies, William Guy Peck - Mathematics - 1855 - 630 pages
...tangent to the curve at the point of contact. Such a line is generally called a normal. Л straight line is perpendicular to a plane when it is perpendicular to every straight line drawn through its foot in that plane. A straight line is perpendicular to a curved surface... ## Elements of Geometry and Conic Sections

Elias Loomis - Conic sections - 1858 - 252 pages
...signifies circumference. SOLID GEOMETRY, BOOK VII. PLANES AND SOLID ANGLES Definitions. 1. A STRAIGHT line is perpendicular to a plane, when it is perpendicular to every straight line which it meets in that plane. Conversely, the plane in this case is per pendicular to... ## Plane and Solid Geometry: To which is Added Plane and Spherical Trigonometry ...

George Roberts Perkins - Geometry - 1860 - 468 pages
...obvious, from our definition of a plane (BI, D. XVII.), that this intersection is a straight line. II. A line is perpendicular to a plane, when it is perpendicular to all the lines in that plane which meet it. III. One plane is perpendicular to another, when every line... ## Elements of Plane and Spherical Trigonometry: With Practical Applications

Benjamin Greenleaf - Geometry - 1861 - 628 pages
...English mathematician. OOK VII. PLANES. — DIEDRAL AND TOLTEDRAL ANGLES. DEFINITIONS. 888. A STRAIGHT line is perpendicular to a plane, when it is perpendicular to every straight line which it meets in that plane. Conversely, the plane, in the same case, is perpendicular... ## Elements of Geometry and Trigonometry: With Practical Applications

Benjamin Greenleaf - Geometry - 1862 - 520 pages
...English mathematician. BOOK VII. PLANES. — DIEDRAL AND P0LYEDRAL ANGLES. DEFINITIONS. 388. A STRAIGHT line is perpendicular to a plane, when it is perpendicular to every straight line which it meets in that plane. Conversely, the plane, in the same case, is perpendicular... ## Mathematics for Practical Men: Being a Common-place Book of Principles ...

Olinthus Gregory - 1863 - 482 pages
...perpendicular to a plane, when it is perpendi cular to every line in that plane which meets it. 3. One plane is perpendicular to another, when every...their common section, is perpendicular to the other. 4. The inclination of one plane to another, or the angle they form between them, is the angle contained... 