SAT数学真题if the length of LM is 7 and the length of MN is 8,which of the following could be the length of LN(LM MN LN are vectors)ANS:14
问题描述：
SAT数学真题
if the length of LM is 7 and the length of MN is 8,which of the following could be the length of LN
(LM MN LN are vectors)
ANS:14
答
由于LM、MN、LN都是向量,那么显然有LM+MN=LN
这就说明这三个向量构成一个三角形,所以在三角形中,一条边事7,一条边是8,由于三角形中两边之和大于第三边,两边只差小于第三边,
所以设LN长度为x的话,那么它的取值范围就是8-7=1小于等于x小于等于8+7=15
所以选在在1到15内的数就可以
Because LM、MN、LN are vectors,we could get LM+MN=LN
so LM MN LN make up a triangle,then we could know that
1