Sum of Angles in 4 Sided Polygon: Proof

Math Easy Solutions

description

In this video I prove that the sum of the angles in any 4-sided polygon, known as a quadrilateral, is equal to 360 degrees. I prove it using two methods. The first method involves drawing parallel lines about 1 point and showing how all the angles add up to form a full revolution, which in turn is by definition equal to 360 degrees. The second proof uses the fact that the sum of the angles in any triangle add up to 180 degrees. Thus by splitting the quadrilateral into 2 triangles, we can then sum all the angles to equal to 180 + 180 which is simply 360 degrees. This is a very useful and interesting video on angles and using parallel lines to determine the corresponding angles so make sure to watch this video!

Download the notes in my video: https://onedrive.live.com/redir?resid=88862EF47BCAF6CD!104289&authkey=!AGhtVMBr70_6aGM&ithint=file%2cpdf

View Video Notes on Steemit: https://steemit.com/mathematics/@mes/sum-of-angles-in-4-sided-polygon-proof