①在△ABC和△DEF中,AB/DE=BC/EF=AC/DF=4,求△DEF的周长之比 ②m :n=1/7:1/6,n:t=1/4:1/3,则m:n:t=?①在△ABC和△DEF中,AB/DE=BC/EF=AC/DF=4,求△DEF的周长之比②m :n=1/7:1/6,n:t=1/4:1/3,则m:n:t=?
问题描述：
①在△ABC和△DEF中,AB/DE=BC/EF=AC/DF=4,求△DEF的周长之比 ②m :n=1/7:1/6,n:t=1/4:1/3,则m:n:t=?
①在△ABC和△DEF中,AB/DE=BC/EF=AC/DF=4,求△DEF的周长之比
②m :n=1/7:1/6,n:t=1/4:1/3,则m:n:t=?
答
①在△ABC和△DEF中,AB/DE=BC/EF=AC/DF=4,求△ABC与△DEF的周长之比
因为AB/DE=BC/EF=AC/DF
所以：△ABC与△DEF相似.周长比等于相似比
△ABC与△DEF的周长之比＝4
②m :n=1/7:1/6,n:t=1/4:1/3,则m:n:t=?
因为m :n=1/7:1/6 所以 m=(6/7)n
因为n:t=1/4:1/3 所以 t=(4/3)n
所以：m:n:t＝(6/7)n：n：(4/3)n＝6/7 :1 :4/3