There is a cylindrical iron block with a base radius of 15 cm and a height of 18 cm. Now it is going to be cast into a conical iron block with a bottom diameter of 20cm. How many centimeters is the height of the cast conical iron block?
有一块圆柱形铁块，底面半径是15cm，高18cm．现在要将它铸造成一个底面直径为20cm的圆锥形铁块，铸成的圆锥形铁块高是多少厘米？
<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">10 ** 2</gadget>
<output>100</output>

<gadget id="calculator">3.14 * 100</gadget>
<output>314</output>

<gadget id="calculator">2 / 314</gadget>
<output>1/157 = around 0.006369</output>

<gadget id="calculator">3.14 * 225 * 18 * (1/157)</gadget>
<output>81</output>

<result>81</result>