If the radius of the base of the cylinder is enlarged to 3 times of the original, to keep the side area of the cylinder unchanged, how much should its height be reduced to the original
圆柱的底面半径扩大到原来的3倍，要使圆柱的侧面积不变，它的高应缩小到原来的多少
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>