A mobile red flag has a base of 28 centimeters and a height of 35 centimeters. If 12 such red flags are to be made, how many square centimeters of red silk do we need at least?
一种流动红旗的底是28厘米，高是35厘米，如果要做12面这样的红旗，至少需要多少平方厘米的红丝绸？
<gadget id="calculator">35 / 2</gadget>
<output>35/2 = around 17.5</output>

<gadget id="calculator">28 * (35/2) * 12</gadget>
<output>5_880</output>

<result>5_880</result>