Seven coins of three different sizes are placed flat on a table, arranged as shown in the diagram. Each coin, except the center one, touches three other coins. The center coin touches all of the other coins. If the coins labelled C_3 have a radius of 3\:cm, and those labelled C_2 have radius 2\:cm, then the radius of the coin labelled X is closest to
Answer Choices
A. 0.615\:cm
B. 0.620\:cm
C. 0.610\:cm
D. 0.605\:cm
E. 0.625\:cm