When a straight line standing on another straight line makes the adjacent angles equal to one another, each of the angles is called a right angle ; and the straight line which stands on the other is called a perpendicular to it.
Geometry Without Axioms; Or the First Book of Euclid's Elements. With ... - Σελίδα 51
των Thomas Perronet Thompson - 1833 - 150 σελίδες
Πλήρης προβολή -