In this video there is a demonstartion showing the sum of angles in a triangle.  You can try it for yourself.  Use a straight edge and try different types of triangles.  Don't worry if you don't have coloured paper, just mark the angles of each triangle so you don't mix them up with other triangles.  

Please contact me if you need help. Send a preferred number and time that is best to call.  shaun.fletcher@nbed.nb.ca