After unfolding the sides of a cylinder whose base circumference is 15.7 cm, a square is obtained. What is the side area of the cylinder?
把一个底面周长是15.7厘米的圆柱侧面展开后，得到一个正方形，这个圆柱的侧面积是多少？
<gadget id="calculator">15.7 * 15.7</gadget>
<output>246.49</output>

<result>246.49</result>