tentukan persamaan lingkaran yang berpusat dititik (-2,1) dan melalui titik (2,-3)

r^2 = (x-a)^2 + (y-b)^2
= (2+2)^2 + (-3-1)^2
= 4^2 + (-4)^2
= 16 + 16
= 32

pers. ling
(x-a)^2 + (y-b)^2 = r^2
(x+2)^2 + (y-1)^2 = 32

Pusat (-2, 1)
(x - (-2))^2 + (y - 1)^2 = r^2
(x + 2)^2 + (y - 1)^2 = r^2
Melalui (2, -3)
(2 + 2)^2 + (-3 - 1)^2 = r^2
(4)^2 + (-4)^2 = r^2
16 + 16 = r^2
32 = r^2
Persamaan lingkaran
(x + 2)^2 + (y - 1)^2 = 32

x^2 + 4x + 4 + y^2 - 2y + 1 = 32
x^2 + y^2 + 4x - 2y - 27 = 0