There are three cylindrical steel materials with a length of 0.5 meters and a cross-sectional diameter of 6 centimeters. If they are welded together, the surface area will be reduced by how many square centimeters.
有三根长都是0.5米，横截面直径都是6厘米的圆柱形钢材，把它们焊接在一起，表面积减少了多少平方厘米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9 * 4</gadget>
<output>113.04</output>

<result>113.04</result>