If the difference between the volumes of two cylinders and cones with the same base and height is 9 cubic decimeters, what is the volume of the cone?
两个等底等高的圆柱体和圆锥体的体积相差9立方分米，圆锥的体积是多少立方分米．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<result>9/2 = around 4.5</result>