If the radius of a circle with a circumference of 20 decimeters is increased by 3 times, what is the circumference in decimeters?
将一个周长是20分米的圆的半径扩大原来的3倍，则周长变为多少分米．
<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<result>60</result>