The difference between the volumes of a cylinder and a cone with the same base and height is 6.28 cubic centimeters, what is the sum of their volumes in cubic centimeters?
等底等高的圆柱和圆锥的体积相差6.28立方厘米，它们的体积之和是多少立方厘米．
<gadget id="calculator">6.28 * 2</gadget>
<output>12.56</output>

<result>12.56</result>