rectangle with a length of 30 cm and a width of 15 cm is rolled into a cylinder, what is the lateral area of the cylinder in square centimeters?
将一个长30厘米，宽15厘米的长方形卷成一个圆柱筒，这个圆柱筒的侧面积是多少平方厘米．
<gadget id="calculator">30 * 15</gadget>
<output>450</output>

<result>450</result>