Angles of a Triangle

This morning in math we investigated the angles of a triangle. Firstly, I drew an equilateral triangle and carefully cut it out. I then tore out the three sides of the triangle and pieced it together just like a puzzle on an imaginary line, I repeated this procedure using a right-angled triangle and figured out that the angles of the triangles I tore off added up to 180°(because they were on a straight line).