How many countries are Sara’s friends from? A. Two. B. Three. C. Four. 听下面一段材料.回答第16至第18题. 【查看更多】
题目列表(包括答案和解析)
If the figure 6 is composed of 24 equilateral triangles,then how many non-congruent distinct right triangles with vertices on the intersecting points are possible in this figure( )