Peter’s father and mother are not busy this evening. He wants to have dinner with ______. A. us B. them C. him D. her 答案:B如图,线段AC=6,线段BC=15,点M是AC的中点,在CB上取一点N,使得NB=2CN.(1)求CN的长?(2)求MN的长?
(1)5;(2)8
【解析】试题分析:(1)NB=2CN,则有CN=BC,从而可求;
(2)因为点M是AC的中点,则有MC=AM=AC,又因为NB=2CN,则有CN=BC,故MN=MC+NC可求.
试题解析:(1)∵CN=2NB,且BC=15
∴CN=BC=×15=5,
(2) ∵M是AC的中点,且AC=6
∴MC=AM=AC=×6=3,
∴MN=MC+N...