Question

Show that (2, 1) is the circum-centre of the triangle formed by the vertices (3, 1), (2, 2) and (1, 1).

Answer 1

$A(2,1)$ $B(3,1)$ $C(2,2)$ $D(1,1)$

$A/Q$. Let $(2,1)$ is circumcenter, then

$AB=AC=AD$

$AB=\sqrt{1^2+0}=1$

$AC=\sqrt{0^2+1^2}=1$

$AD=\sqrt{1^2}=1$

Hence $(2,1)$ is circumcenter.