A cylinder has a base circumference of 28 cm and a height of 5.4 cm. It is known that its side area is 7 times the side area of another cylinder. The base circumference of another cylinder is 9 cm. What is its height?
一个圆柱的底面周长是28cm，高5.4cm，已知它的侧面积是另一个圆柱侧面积的7倍，另一个圆柱的底面周长是9cm，它的高应该是多少？
<gadget id="calculator">5.4 / 7 / 9</gadget>
<output>0.085714</output>

<gadget id="calculator">28 * 0.085714</gadget>
<output>2.399992</output>

<result>2.399992</result>