Everyone learns the number one rule about triangles in high school: the angles of a triangle add up to 180 degrees. But did you know that sometimes they don't? Triangles are much more interesting than ...

Many children's concept of a triangle is limited to the familiar equilateral triangle with a horizontal base. In this lesson, students will explore and identify a variety of triangular shapes using ...

Well, what is the best way to cut a sandwich in half? Surely triangles don't really have "more sandwich," right? That's geometry and the law of conservation of matter. But something about the ...