问题 选择题
已知△ABC∽△DEF,且△ABC的三边长分别为4,5,6,△DEF的一边长为2,则△DEF的周长为(   )

A.7.5
B.6
C.5或6
D.5或6或7.5
答案

答案:D

选择题

读以下三幅图:

请回答:

(1)图1、2各反映了哪一大河流域的文明成就?两地人们当时各使用什么文字书写?

                                                                                                                                                             

(2)能代表图1所反映文明古国的另一典型文明建筑是什么?

                                                                                                                                                            

(3)图3所示数字的发明者和传播者各是谁?

                                                                                                                                                              

(4)基于以上你有何认识?