A cylinder and a cone with the same base and height. The volume of the cylinder is 9 cubic centimeters. What is the sum of their volumes?
等底等高的圆柱和圆锥，圆柱的体积是9立方厘米，它们的体积之和是多少．
<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">9 + 3</gadget>
<output>12</output>

<result>12</result>