After the height of a cylinder is increased by 10cm, its surface area is increased by 314cm, what is the area of the base of the cylinder?
一个圆柱体的高增加10cm后，它的表面积比原来增加了314cm，这个圆柱体的底面积是多少．
<gadget id="calculator">314 / 10 / 3.14 / 2</gadget>
<output>5</output>

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

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<result>78.5</result>