If a cylinder is sawn in half from diameter to height, the surface area increases by 60 square centimeters. Find the lateral area of the cylinder.
一个圆柱，从直径沿着高把圆柱锯成两半，表面积增加60平方厘米．求圆柱的侧面积．
<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">3.14 * 30</gadget>
<output>94.2</output>

<result>94.2</result>