유클리드 원론 3권 (Euclid Elements III)
Definitions Definition 1 Equal circles are those whose diameters are equal, or whose radii are equal. Definition 2 A straight line is said to touch a circle which, meeting the circle and being produced, does not cut the circle. Definition 3 Circles are said to touch one another which meet one another but do not cut one another. Definition 4 Straight lines in a circle are said to be equally dista..