Putting two identical half cylinders together to form a cylinder, the surface area is reduced by 72 square centimeters. Given that the radius of the base of the cylinder is 3 cm, what is the lateral area of the cylinder in square centimeters?
把两个完全一样的半圆柱拼成一个圆柱，表面积减少72平方厘米．已知这个圆柱的底面半径是3厘米，那么这个圆柱的侧面积是多少平方厘米．
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<gadget id="calculator">72 / 2 / 6</gadget>
<output>6</output>

<gadget id="calculator">2 * 3.14 * 3 * 6</gadget>
<output>113.04</output>

<result>113.04</result>