A cone has a base radius of 6 cm and a height of 5 cm. If you cut it in half from its apex down its height, how many square centimeters will its surface area increase?
一个圆锥的底面半径是6厘米，高是5厘米．从它的顶点向下沿着高将它等分切成两半，表面积会增加多少平方厘米．
<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">12 * (5/2) * 2</gadget>
<output>60</output>

<result>60</result>