A cylindrical side surface is a square, the circumference of the bottom of this cylinder is 15.7 decimeters, what is the side area in square decimeters?
一个圆柱侧面展开是一个正方形，这个圆柱体底面周长15.7分米，侧面积是多少平方分米．
<gadget id="calculator">15.7 * 15.7</gadget>
<output>246.49</output>

<result>246.49</result>