A cylindrical iron block with a base diameter of 6 decimeters and a height of 3 decimeters is melted into a conical iron block with a base radius of 5 decimeters. What is the height of the conical iron block?
把一个底面直径是6分米，高3分米的圆柱形铁块，熔化成一个底面半径是5分米的圆锥形铁块，圆锥形铁块高是多少分米？
<gadget id="calculator">81 / 25</gadget>
<output>81/25 = around 3.24</output>

<result>81/25 = around 3.24</result>