The height of a cylinder is 20 cm. If its height is shortened by 3 centimeters, its surface area will be reduced by 94.2 square centimeters. What is the original surface area of this cylinder?
一个圆柱的高是20厘米．如果把它的高截短3厘米，它的表面积就减少94.2平方厘米，这个圆柱的表面积原来是多少？
<gadget id="calculator">94.2 / 3 / 3.14 / 2</gadget>
<output>5</output>

<gadget id="calculator">3.14 * 5 * 2 * 20</gadget>
<output>628</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25 * 2</gadget>
<output>157</output>

<gadget id="calculator">628 + 157</gadget>
<output>785</output>

<result>785</result>