A cone with a base radius of 4 cm and a height of 6 cm is cut along the apex to the center of the circle, how much does the surface area increase in square centimeters?
一个圆锥的底面半径是4厘米，高是6厘米，沿着顶点到圆心切开，表面积增加多少平方厘米．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">4 * 2 * 3 * 2</gadget>
<output>48</output>

<result>48</result>