∵45AF=12,∴AF=452,
∵BE45=cot30°=3,∴BE=453,
∴AB=EF+AF+BE=25+452+453(米),
又∵45BC=sin30°=12,∴BC=90(米),
∵∠B=30°,∴BC的坡度为tan30°=1:3.
答:坝底AB的长为25+452+453(米)、迎风坡BC的长为90米,BC的坡度为1:3.
追问45为什么在AF的前面啊??
追答![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/7c1ed21b0ef41bd5a88613f253da81cb38db3dda?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
排版问题
追问谢谢,不过麻烦下,我没学过余切,怎样不用余切求啊??
追答cot30=1/tan30,换一下就可以了