Of all the triangles whose all sides are integers,how many triangles whose sides are 9 and 12?

分类: 作业答案 • 2022-01-09 18:02:21

问题描述：

Of all the triangles whose all sides are integers,how many triangles whose sides are 9 and 12?
A.21 B.3 C.17 D无数

答

C
三角形两边之和大于大于第三边,两边之差小于第三边,所以第三条边的长度是4-20间的所有整数,共17个.