There is some water in a cylindrical glass tank. Put a cylindrical iron block with a bottom radius of 5 cm into the glass tank. If the iron block completely penetrates into the water, the water level in the glass fiber reinforced plastic will be 10 cm higher than before. Lift the iron block from the water in a vertical direction. When the iron block is 8 cm above the water surface, the water in the glass tank will drop by 4 cm. Find the volume of the cylindrical iron block.
一个圆柱形玻璃缸里有一些水，把一个底面半径为5厘米的圆柱形铁块放入玻璃缸中，如果铁块全部侵入水中，玻璃钢中的水面比原来高了10厘米，如果沿铁块竖直方向把铁块从水中提起，铁块露出水面8厘米后，玻璃缸里的水就一下降4厘米，求这个圆柱形铁块的体积．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<gadget id="calculator">3.14 * 25 * 2 * 10</gadget>
<output>1_570</output>

<result>1_570</result>