Cut a cylinder with a diameter of 6 cm at the bottom and a height of 5 cm along the diameter of the bottom, how much does the surface area increase in cm**2.
把底面直径6cm，高5cm的圆柱沿底面直径切开，表面积增加了多少cm**2．
<gadget id="calculator">6 * 5 * 2</gadget>
<output>60</output>

<result>60</result>