The radius of the base is 10 cm and the height is 2.5 cm. Find the lateral area of the cylinder.
底面半径是10厘米，高是2.5厘米．求圆柱的侧面积．
<gadget id="calculator">3.14 * 2 * 10 * 2.5</gadget>
<output>157</output>

<result>157</result>