请教这两题思路

mariezhu

In triangle ABC, point X is the midpoint of side AC and point Y is the midpoint of side BC. If R is the midpoint ot line segment XC and if point S is the midpoint of YC, what is the area of triangle RCS?

1.       the area of triangle ABX is 32

2.       the length of one of the altitudes of triangle ABC is 8

an:A

Which is the volume of a certain cube?

1.       The sum of the areas of the faces of the cube is 54

2.       The greatest possible distance between two points on the cube is 3 square root 3

An

juniya

1。自己先画一个图形

    三角形ABC的面积应该是64，也不是1/4啊，应该是1/16吧

2. 6a^2=54

    3a^2=(3sqr3)^2

[此贴子已经被作者于2004-5-15 7:46:37编辑过]

mariezhu

看来得好好复习数学了,基本的数学单词还不清楚,昨晚认为cube是长方体,所以反复列式子,就是觉得不能得出体积,唉汗颜呐,这大概是CD数学史上最弱智的帖子了. NN们以后多帮我啊!

关于第一题,juniya美眉是不是认为RS肯定是AB的1/4, 三角形CRS的高也是C到AB高的1/4?

严重感谢!!

tulipmontreal

第一题是这样, 三角形RCS是整个大三角形的四份之一,不是32份之一. A答案正确, 2条件不充分.

mariezhu

麻烦GG再讲讲?

我觉得底是1/4,高也是1/4,应该是1/16啊

Please correct me if i were wrong. Many thanks