Two identical rectangular sheets of paper, 16 cm long and 4 cm wide. One is rolled horizontally into a cylinder, and the other is rolled vertically into a cylinder. Are the lateral areas of the two cylinders the same size? Why, please figure it out.
两张完全一样的长方形纸，长16厘米，宽4厘米．一张横着卷成圆柱形，另一张竖着卷成圆柱形．两个圆柱形的侧面积一样大吗？为什么，请算出来．
<gadget id="calculator">16 * 4</gadget>
<output>64</output>

<result>64</result>