A rectangular cistern is filled with a piece of iron with a side length of 5 cm. The water surface rises by 9 cm. When the iron block rises to a height of 8 cm above the water surface, the water level falls by 4 cm. What is the volume of the iron block in cubic centimeters?
一个长方形蓄水池，把一块底面边长为5厘米正方形的铁块全部放进去，水面上升9厘米，当铁块露出水面8厘米高，水面则下降4厘米，铁块体积多少立方厘米．
<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">2 * 9</gadget>
<output>18</output>

<gadget id="calculator">5 * 5 * 18</gadget>
<output>450</output>

<result>450</result>