1 Let $C_{1}$ and $C_{2}$ be distinct circles of radius $7 \mathrm{~cm}$ that are in the same plane and tangent to each other. Find the number of circles of radius $26 \mathrm{~cm}$ in this plane that are tangent to both $C_{1}$ and $C_{2}$.
(A) 2
(B) 4
(C) 6
(D) 8
(E) none of the above
1 Answer: (C)
As seen from the diagram below, there are 6 circles that are tangent to both $C_{1}$ and $C_{2}$.