If two circles be so drawen, that the one be within the other, and that they touche one an other: If a line bee drawen by bothe their centres, and so forthe in lengthe, that line shall runne to that pointe, where the circles do touche.
Example.
The one circle, which is the greattest and vttermost is A.B.C, the other circle that is ye lesser, and is drawen within the firste, is A.D.E. The cẽtre of the greater circle is F, and the centre of the lesser circle is G, the pointe where they touche is A. And now you may see the truthe of the theoreme so plainely, that it needeth no farther declaracion. For you maye see, that drawinge a line from F. to G, and so forth in lengthe, vntill it come to the circumference, it wyll lighte in the very poincte A, where the circles touche one an other.
[ The Lvij. Theoreme.]
If two circles bee drawen so one withoute an other, that their edges doo touche and a right line bee drawnenne frome the centre of the one to the centre of the other, that line shall passe by the place of their touching.
Example.
The firste circle is A.B.E, and his centre is K, The secõd circle is D.B.C, and his cẽtre is H, the point wher they do touch is B. Nowe doo you se that the line K.H, whiche is drawen
from K, that is centre of the firste circle, vnto H, beyng centre of the second circle, doth passe (as it must nedes by the pointe B,) whiche is the verye poynte wher they do to touche together.