> 数学 >
如图,M,N为线段如图,M、N为线段AB上两点,且AM:MB=1:3,AN:NB=5:7.若MN=2,求AB的长
用方程的思想
人气:260 ℃ 时间:2019-11-25 12:37:35
解答
因为,AM/AB = AM:(AM+MB) = 1/(1+3) = 1/4 ,AN/AB = AN/(AN+NB) = 5/(5+7) = 5/12 ,所以,AM = (1/4)AB ,AN = (5/12)AB ;因为,MN = AN-AM = (5/12-1/4)AB = (1/6)AB ,所以,AB = 6MN = 12 .
推荐
猜你喜欢
© 2024 79432.Com All Rights Reserved.
电脑版|手机版