A cylindrical bucket with a height of 0.8 meters and a bottom radius of 0.2 meters is half filled with water. How many liters of water are there in the bucket?
一个圆柱形水桶，高0.8米，底面半径是0.2米，装了半桶水，桶中水有多少升？
<gadget id="calculator">0.2 * 10</gadget>
<output>2</output>

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

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<gadget id="calculator">3.14 * 4 * 0.8 * 5</gadget>
<output>50.24</output>

<result>50.24</result>