一个三角形三边长分别是根号五根号七根号六 分别用海伦公式和秦九韶公式求出。 如果一个三角形的三边的长分别为a、b、c，那么可以根据秦九韶...
\u5df2\u77e5\u4e09\u89d2\u5f62\u4e09\u8fb9\u957f\u4e3aa=\u6839\u53f75,b=\u6839\u53f76,c=\u6839\u53f77,\u8ba1\u7b97\u8be5\u4e09\u89d2\u5f62\u7684\u9762\u79ef\u5229\u7528\u5357\u5b8b\u79e6\u4e5d\u97f6\u516c\u5f0f\uff08PS\uff1ap\uff1d\uff08a\uff0bb\uff0bc\uff09\uff06\uff0347\uff1b2\uff1d15\uff06\uff0347\uff1b2\u6240\u4ee5S\uff1d\u221a\uff3b\uff0815\uff06\uff0347\uff1b2\uff09\uff0815\uff06\uff0347\uff1b2\uff0d4\uff09\uff0815\uff06\uff0347\uff1b2\uff0d5\uff09\uff0815\uff06\uff0347\uff1b2\uff0d6\uff09\uff3d\uff1d\u221a\uff081575\uff06\uff0347\uff1b16\uff09\uff1d\uff0815\uff06\uff0347\uff1b4\uff09\u221a7
\u8bf7\u53c2\u8003http://www.jyeoo.com/Math/Ques/Detail/91bb8154-3b56-4fc4-9382-9ef99e535d95
如图
海伦公式S=√［p(p-a)(p-b)(p-c)］=√［(√5+√6+√7)(√5+√6-√7)(√5-√6+√7)(√6+√7-√5)］/16
=√［(8+2√42)(2√42-8)］/16=√(13/2)
其中p为半周长，a,b,c为三边长
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