Geometry Problem 640. Archimedes' Book of Lemmas: Proposition 1.
1. Internally Tangent Circles at A
If two circles touch at A (internally), and if BC and DE are parallel diameters, then ACE is a straight line.
2. Externally Tangent Circles at A.
If two circles touch at A (externally), and if BC and DE are parallel diameters, then ACE is a straight line.
Books of Lemmas Index
Proposition 1
Proposition 2
Proposition 3
Proposition 4
Proposition 5
Proposition 6
Proposition 7
Proposition 8
Proposition 9
Proposition 10
Proposition 11
Proposition 12
Proposition 13
Proposition 14
Proposition 15
