Cut a circle with a radius of 4 cm along its diameter, divide it into several parts on average, and form an approximate rectangle. What is the length of this rectangle in π cm?
将一个半径4厘米的圆沿着它的直径剪开，平均分成若干份，拼成一个近似的长方形，这长方形的长是多少π厘米．
<gadget id="calculator">2 / 2</gadget>
<output>1</output>

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

<result>4</result>