The diameter of the base of the cylinder is 30cm, the height is 30cm, what is the volume?
圆柱的底面直径为30cm，高是30cm，体积是多少？
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">15 ** 2</gadget>
<output>225</output>

<gadget id="calculator">3.14 * 225 * 30</gadget>
<output>21_195</output>

<result>21_195</result>