A mathematical geometry in grade three, I hope the master can help me choose a three-dimensional problem and explain why! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! Choosing a is simple. From the front, there is a dotted line in the middle, indicating that the other side is in the middle, which can also be consistent with the isosceles triangle seen from the top view. Then it is impossible to see another dotted line from the side. The front view is from the front, not inclined. Be clear not to be fooled by the picture.