Question

Given: A(2,1), B(0,5), C(-1,2), AB and BC, center point (1,3) and r=√5.

Find the equation of the circle.

Answer 1

Below in bold.

Explanation:

To find an equation of a circle we need the length of the radius and the coordinates of the centre.

The general form is (x - j)^2 + (y - k)^2 = r^2 where (j, k) is the centre and r is the radius.

So our equation is:

(x - 1)^2 + (y - 3)^2 = (√5)^2

(x - 1)^2 + (y - 3)^2 = 5.