A conical camping tent has a base radius of 2 meters and a height of 1.8 meters. How big is the tent space? (thickness is ignored)
一个近似于圆锥形的野营帐篷，它的底面半径是2米，高是1.8米．帐篷的空间有多大？(厚度忽略不计)
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">2 ** 2</gadget>
<output>4</output>

<gadget id="calculator">(1/3) * 3.14 * 4 * 1.8</gadget>
<output>7.536</output>

<result>7.536</result>