Posts tagged 'right-angles-to-plane'
G.505 line at right angles to a plane
A:term:segment <G.4> is:term:**at right angles to a plane** <right-angles-to-plane>, when it makes:term:right angles <G.33> with all the segments which meet it and are in the:term:plane <G.7>.
G.506 segment set right
If a segment be set up at right angles to two segments which cut one another, at their common point of section, it is at right angles to the plane through them.
G.507 segment set right
If a segment be set up at right angles to three segments which meet one another, at their common point of section, the three segments are in one plane.
G.508 segments right angles
If two segments be at right angles to the same plane, the segments is parallel.
G.510 segments parallel right
If two segments be parallel, and one of them be at right angles to any plane, the remaining one is at right angles to the same plane.
G.511 straight lines parallel
Straight lines which are parallel to the same segment and are not in the same plane with it are also parallel to one another.
G.513 elevated point draw
From a given elevated point to draw a segment perpendicular to a given plane.
G.514 set segment right
To set up a segment at right angles to a given plane from a given point in it.
G.515 point segments set
From the same point two segments cannot be set up at right angles to the same plane on the same side.
G.517 planes segment right
Planes to which the same segment is at right angles is parallel.
G.518 segments meeting parallel
If two segments meeting one another be parallel to two segments meeting one another, not being in the same plane, the planes through them are parallel.
G.522 segment right angles
If a segment be at right angles to any plane, all the planes through it is at right angles to the same plane.
G.523 planes cut right
If two planes which cut one another be at right angles to any plane, their common section is at right angles to the same plane.
G.528 construct a solid angle out of three plane
Construct a solid angle out of three plane angles two of which, taken together in any manner, are greater than the remaining one: thus the three angles must be less than four right angles.
G.532 segment point construct
On a given segment, and at a given point on it, to construct a solid angle equal to a given solid angle.
G.577 spheres center inscribe
Given two spheres about the same center, to inscribe in the greater sphere a polyhedral solid which does not touch the lesser sphere at its surface.
G.592 construct pyramid comprehend
To construct a :term:`pyramid <G.553>`, to comprehend it in a given :term:`sphere <G.575>`, and to prove that the :term:`square <G.63>` on the :term:`diameter of the sphere <G.576>` is one and a half times the square on the side of the pyramid.
G.594 construct an octahedron and comprehend it in a
Construct an octahedron and comprehend it in a sphere, as in the preceding case; and to prove that the square on the diameter of the sphere is double of the square on the side of the octahedron.
G.595 construct a cube and comprehend it in a
Construct a cube and comprehend it in a sphere, like the pyramid; and to prove that the square on the diameter of the sphere is triple of the square on the side of the cube.
G.597 construct an icosahedron and comprehend it in a
Construct an icosahedron and comprehend it in a sphere, like the aforesaid figures; and to prove that the side of the icosahedron is the irrational segment called minor.
G.600 construct a dodecahedron and comprehend it in a
Construct a dodecahedron and comprehend it in a sphere, like the aforesaid figures, and to prove that the side of the dodecahedron is the irrational segment called apotome.