Area of a circle, how to get the formula.

Read a more complete explanation here: http://pythagoreanmath.com/complete-explanation-for-area-of-a-circle-formula/

πr(squared) gives you the area of a circle, but where does it come from? Here is a simple explanation.

Reddit discussion about the video here: https://www.reddit.com/r/pythagoreanmath/comments/5wt8ow/area_of_a_circle_video/