A cylinder with a base circumference of 25.12 cm divides its base into several sectors, cuts several pieces along the sectors and assembles them into an approximate cuboid, the surface area increases by 40 square centimeters. What is the volume of this cylinder?
一个底面周长为25.12厘米的圆柱体，把它的底面等分成若干个扇形，沿着扇形切开若干块然后拼成一个近似的长方体，表面积增加了40平方厘米．这个圆柱体的体积是多少？
<gadget id="calculator">25.12 / 3.14 / 2</gadget>
<output>4</output>

<gadget id="calculator">4 ** 2</gadget>
<output>16</output>

<gadget id="calculator">40 / 2 / 4</gadget>
<output>5</output>

<gadget id="calculator">3.14 * 16 * 5</gadget>
<output>251.2</output>

<result>251.2</result>