An equilateral triangle with a side length of 10 cm has a disk with a radius of 2 cm outside. The disk moves close to the outside of the triangle. Find the area it sweeps.
一个正三角形边长为10厘米，外有一个半径为2厘米的圆片，圆片紧贴三角形外边运动，求它扫过的面积．
<gadget id="calculator">10 * 3</gadget>
<output>30</output>

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

<gadget id="calculator">30 * 4</gadget>
<output>120</output>

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

<gadget id="calculator">3.14 * 4</gadget>
<output>12.56</output>

<gadget id="calculator">120 + 12.56</gadget>
<output>132.56</output>

<result>132.56</result>