A circle is assembled into a rectangle by cutting. If the radius of the circle is 4 cm, what is the perimeter of the rectangle in cm?
把一个圆通过切割拼成一个长方形．如果圆的半径是4厘米，这个长方形的周长是多少厘米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

<gadget id="calculator">3.14 * 4 * 1</gadget>
<output>12.56</output>

<gadget id="calculator">12.56 + 4</gadget>
<output>16.56</output>

<gadget id="calculator">16.56 * 2</gadget>
<output>33.12</output>

<result>33.12</result>