Ex: Find the circumcentre of the triangle formed by the points (-2,3) (2,-1) and (4,0)
Shift the origin to (-2,3) then the transformed vertices are (0,0) (4,-4) (6,-3)
2x1 2y1 -(x12 +y12) 2x1
2x2 2y2 -(x22 +y22) 2y2
1
2
3
Circumcentre = (
2/
1 ,
3/
1) Where
1=(2x1)(2y2) - (2x2)(2y1)
In the above example we get
8 -8 -32 8 simplify the row if possible the we get 1 -1 -4 1
12 -6 -45 12 4 -2 -15 4
= {(-1)(-15) - (-2)(-4)/(-2) - (-4) , (-4)(4) - (-15)(1)/(-2) - (-4)}
= {7/2 , -1/2}
But we hav to transform bak the equation to origin
Circum centre = {7/2+(-2), -1/2+3)} = {3/2 , 5/2)
Last step can be omitted if the given vertices are in the form of (0,0) (x1,y1) (x2,y2)