A cylindrical glass with a bottom diameter of 40 cm contains some water, and a conical lead cone with a bottom diameter of 20 cm and a height of 15 cm is completely submerged in the water. When the lead weight is taken out, how many centimeters does the water level in the glass drop?
一个底面直径是40厘米的圆柱形玻璃杯装有一些水，一个底面直径是20厘米、高为15厘米的圆锥形铅锥完全没入水中，当取出铅锤后，杯里的水面下降几厘米？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

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

<gadget id="calculator">(1/3) * 3.14 * 100 * 15</gadget>
<output>1_570</output>

<gadget id="calculator">40 / 2</gadget>
<output>20</output>

<gadget id="calculator">20 ** 2</gadget>
<output>400</output>

<gadget id="calculator">3.14 * 400</gadget>
<output>1_256</output>

<gadget id="calculator">1_570 / 1_256</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>