If a cone has a base radius of 3 cm and a height of 5 cm, if it is cut in half from the apex downwards along the height, the surface area will increase by how many square centimeters.
一个圆锥体的底面半径是3厘米，高是5厘米，从它的顶点向下沿着高将它切成两半，表面积会增加多少平方厘米．
<gadget id="calculator">3 * 2</gadget>
<output>6</output>

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

<gadget id="calculator">6 * (5/2) * 2</gadget>
<output>30</output>

<result>30</result>