2.8-meter-long cylindrical wood is cut into three sections according to the ratio of 1:2:4, and the surface area increases by 60 square decimeters. What is the volume of the longest piece after cutting?
一根长2.8米的圆柱形木材，按1：2：4截成三段后，表面积增加了60平方分米，截下后最长一根的体积是多少？
<gadget id="calculator">60 / 4</gadget>
<output>15</output>

<gadget id="calculator">1 + 2 + 4</gadget>
<output>7</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">2.8 * (4/7)</gadget>
<output>1.6</output>

<gadget id="calculator">15 * 1.6</gadget>
<output>24</output>

<result>24</result>