If the height of a cylinder is reduced by 2 centimeters, the surface area will be reduced by 18.84 square centimeters. What is the area of the base of this cylinder?
一个圆柱，高减少2厘米，表面积就减少18.84平方厘米，这个圆柱的底面积是多少？
<gadget id="calculator">18.84 / 2 / 3.14 / 2</gadget>
<output>1.5</output>

<gadget id="calculator">1.5 ** 2</gadget>
<output>2.25</output>

<gadget id="calculator">3.14 * 2.25</gadget>
<output>7.065</output>

<result>7.065</result>