Orphans¶
The following definitions, postulates, and common notions are not directly cited by any proposition in the main dependency sequence.
V.def.8¶
Heath ID: V.def.8
A proportion in three terms is the least possible.
VII.def.10¶
Heath ID: VII.def.10
An odd-times odd number is that which is measured by an odd number according to an odd number.
XI.def.5¶
Heath ID: XI.def.5
The inclination of a straight line to a plane is, assuming a perpendicular drawn from the extremity of the straight line which is elevated above the plane to the plane, and a straight line joined from the point thus arising to the extremity of the straight line which is in the plane, the angle contained by the straight line so drawn and the straight line standing up.
XI.def.6¶
Heath ID: XI.def.6
The inclination of a plane to a plane is the acute angle contained by the straight lines drawn at right angles to the common section at the same point, one in each of the planes.
XI.def.7¶
Heath ID: XI.def.7
A plane is said to be similarly inclined to a plane as another is to another when the said angles of the inclinations are equal to one another.