A paint roller is 2.4 decimeters long and 5 centimeters in diameter. If it rolls 100 times, how many square decimeters of the wall can be painted?
一个刷油漆的滚筒长2.4分米，直径为5厘米，如果它滚动100周，能刷墙多少平方分米？
<gadget id="calculator">5 / 10</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">3.14 * (1/2) * 2.4 * 100</gadget>
<output>376.8</output>

<result>376.8</result>