The advertising company made a cylindrical light box with a base radius of 1.5 meters and a height of 2.5 meters. What is the maximum area of posters that can be posted on its side?
广告公司制作了一个底面半径1.5米，高2.5米的圆柱形灯箱．它的侧面最多可以张贴多大面积的海报？
<result>23.44</result>