What is a five sided 3D triangle?

Answer 1

Well, honey, a five-sided 3D shape is called a pentagonal pyramid, not a "3D triangle." Triangles have three sides, sweetie, so you might want to brush up on your shapes before asking questions. But hey, at least you're trying to learn, so I'll give you credit for that.

Answer 2

A 3-D TRIANGLE cannot have 5 sides.