在探索圆柱侧面积的计算方法中,结合圆柱的侧面展开图发现:长方形的长=圆柱底面的周长,长方形的宽=圆柱的高;因为“长方形的面积=长×宽”,所以“圆柱的侧面积=底面的周长×高”,公式为:S=Ch=πdh=2πrh。
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/8601a18b87d6277f11d172aa3a381f30e824fc65?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
1.知底面周长和高,求侧面积
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/a08b87d6277f9e2f97f65d9a0d30e924b999f365?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
点拨:运用公式:S=Ch
72×8=576(cm)
2.知底面半径和高,求侧面积
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/b21c8701a18b87d6a981eb8d150828381e30fd65?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
点拨:运用公式S=2πrh(2πr为底面周长)
2×3.14×3×12=18.84×12=226.08(dm)
3.知底面直径和高,求侧面积
![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/86d6277f9e2f0708b9c66a92fb24b899a801f265?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
点拨:运用公式S=πdh(πd为底面周长)
3.14×0.5×1.8=1.57×1.8≈2.83(m)