Jari jari lingkaran x2 + y2 - 2x + 4y - 1 = 0 Kalo hasilnya akar jadi kayak apa??

A =-2, B=4, C= -1

Jari-jari = V(A^2/4+B^2/4 -C)
[tex]r = \sqrt{ \frac{ { - 2}^{2} }{4} + \frac{ {4}^{2}}{4} + 1} \\ \\ r = \sqrt{1 + 4 + 1} \\ r = \sqrt{6} \\ [/tex]