Flexing my Brain: Find Your Centre

I've been meaning to do a post of this type this since I started this blog, hence the "coding" part of the URL. I not sure how this popped into my head, I was just doodling on some paper some paper and somehow came up with.

"If you have three points on the circumference of a circle how do you find the centre of that circle?"

Yes, I do ponder odd things at times. To solve this graphically its pretty simple.

Given points p₁,p₂,and p₃, construct two lines l₁and l₂ by connecting p₁ to p₂,and p₂ to p₃.
Find the centre point of each line m₁ and m₂.
From each of these points construct a line, perpendicular to the parent line and find the point intersection of these two new lines (l₃and l₄).
This point of intersection is the centre of the circle, from there you can calculate any and all other circular goodness you might need.

Click the image for a demonstratrion.