若两圆的半径分别为2和4,且圆心距为7,则两圆的位置关系为( )
A:外切
B:内切
C:外离
D:相交
Do you see the sea? The sea is blue,and it is very large(大的).The sea looks beautiful in a sunny day. If(如果)you swim,in the sea,you know that the water is salty(咸的).Do you like the sea?
如图,AB=CD,AC=BD,且AC交BD于点O,在原图形的基础上,用SSS证明△AOB≌△COD,还需添加的一个条件是( )