Any help would be greatly appreciated. I am a complete novice to this type of stuff. Thanks heaps!
1.) What does it appear to you that the sum of the 3 angles is?
2.) Have you tried this yourself with different quadrilaterals? If so, then what is your conclusion?
3.) Label the interior angles of the triangle (what is their sum?), observe that they are supplementary to the outer angles, and add all 3 pairs. What do you find?