Take a triangular ruler, the two right-angled sides are 20 cm and 30 cm respectively, rotate it around the longer right-angled side as the axis, and find the volume of the obtained shape.
一个三角尺，两个直角边分别为20厘米和30厘米，以较长的直角边为轴旋转一周，求所得形体的体积．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

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

<gadget id="calculator">(1/3) * 3.14 * 400 * 30</gadget>
<output>12_560</output>

<result>12_560</result>