The volume difference between a cone and a cylinder with the same base and height is 1.56 cubic meters. What is the volume of the cone in cubic meters?
一个圆锥与它等底等高的圆柱的体积相差1.56立方米，圆锥的体积是多少立方米．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">1.56 / 2</gadget>
<output>0.78</output>

<result>0.78</result>