Xiaoming uses a cylindrical glass vessel with a base radius of 6 cm and a height of 15 cm to fill part of the water. A conical plumb weight with a height of 9 cm is immersed in the water. When the plumb weight is taken out of the water, the water level drops by 0.5 cm. How many square centimeters is the base of the hammer?
小明用一个底面半径是6厘米，高15厘米的圆柱形玻璃器皿装一部分水，水中浸没着一个高9厘米的圆锥形铅锤，当铅锤从水中取出后，水面下降了0.5厘米，这个铅锤的底面是多少平方厘米？
<gadget id="calculator">6 ** 2</gadget>
<output>36</output>

<gadget id="calculator">3.14 * 36 * 0.5</gadget>
<output>56.52</output>

<gadget id="calculator">3 / 9</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">56.52 * (1/3)</gadget>
<output>18.84</output>

<result>18.84</result>