On the same side of a straight line three circles are drawn as follows: a circle with a radius of 4 inches is tangent to the line, the other two circles are equal, and each is tangent to the line and to the other two circles. The radius of the equal circles is:
<spanclass=′latex−bold′>(A)</span>24<spanclass=′latex−bold′>(B)</span>20<spanclass=′latex−bold′>(C)</span>18<spanclass=′latex−bold′>(D)</span>16<spanclass=′latex−bold′>(E)</span>12