If the sum of the volumes of a cylinder and a cone with the same base and height is 10.8 cubic decimeters, what is the volume of the cone in cubic decimeters?
等底等高的圆柱和圆锥，它们的体积之和是10.8立方分米，那么圆锥的体积是多少立方分米．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">10.8 * (1/4)</gadget>
<output>2.7</output>

<result>2.7</result>