Persamaan lingkaran yg berpusat di (3,-2) dan menyinggung garis 4x-3y+2=0 adalah...

a = 4
b = -3
c = 2
x1 = 3
y1 = -2

==Jawaban==
r = (ax1 + by1 + c)/√(a² + b²)
r = (4.3 + (-3).(-2) + 2)/√(4² + (-3)²)
r = (12 + 6 + 2)/√(16 + 9)
r = 20/√25
r = 20/5
r = 4

Maka
(x - 3)² + (y + 2)² = 4²
x² - 6x + 9 + y² + 4y + 4 = 16
x² + y² - 6x + 4y - 3 = 0