Answer:
Option B
Explanation:
Given, points (5,7) ,(2,-2) and (-2,0) lie on circle
Let (h,k) be centre of circle
∴ OA=OC

∴ (h+2)2+k2=(h−5)2+(k−7)2
⇒h2+4h+4+k2=h2−10h+25+k2−14k+49
⇒14h+14k=70
h+k=5 .............(i)
When OA=OB
∴ (h+2)2+k2=(h−2)2+(k+2)2
⇒h2+4h+4+k2=h2−4h+4+k2+4k+4
⇒8h−4k=4
2h-k=1 .........(ii)
From eqs. (i) and (ii) we get
h=2, k=3
∴ Centre of circle (2,3)
Radius of circle OA= √(2+2)2+32
OA= √42+32=√16+9=√25=5units