If the height of a cylinder is reduced by 4 cm, the surface area will be reduced by 75.36 square centimeters. What is the area of the base of this cylinder?
一个圆柱体，高减少4厘米，表面积就减少75.36平方厘米，求这个圆柱的底面积是多少？
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9</gadget>
<output>28.26</output>

<result>28.26</result>