The radius of the base of a cylinder is 3 cm, what is the increase in surface area if it is sawn into two cylinders.
一个圆柱体的底面半径是3厘米，将它锯成两个圆柱体后表面积增加多少．
<gadget id="calculator">3 ** 2</gadget>
<output>9</output>

<gadget id="calculator">3.14 * 9 * 2</gadget>
<output>56.52</output>

<result>56.52</result>