Triangles from maths

In maths we have been learning to make triangles out of pretzels and these are the some of the ways to do some triangles with pretzels. One triangle was called the equilateral triangle. These are the things you might like to do with your pretzels. We have been doing it for two days and we had to get a piece of paper and then Elizabeth said draw triangles. After we finished making the triangle out of pretzels Elizabeth came around and asked what was the same and different about the triangles. She wanted us to make this triangle called equilateral out of pretzels.

What is the name of this triangle?  How do you know?