A cylindrical iron bar with a length of 1 meter and a base radius of 5 cm is sawed into 4 sections, each section is still a cylinder, and the surface area is increased by how many square centimeters compared to the original.
把一根长1米，底面半径是5厘米的圆柱体铁棒锯成4段，每段仍是圆柱体，表面积比原来增加了多少平方厘米．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25 * 6</gadget>
<output>471</output>

<result>471</result>