The diameter of the base of a cone is 4 cm and the height is 3 cm. If you cut it from the apex down to form two halves of the same shape, how many square centimeters will the surface area increase?
一个圆锥的底面直径是4厘米，高3厘米，把它从顶点往下一刀切开，成为形状相同的两半，表面积增加多少平方厘米？
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">4 * (3/2) * 2</gadget>
<output>12</output>

<result>12</result>