Let a circle C pass through the points (4, 2) and (0, 2), and its centre lie on 3x + 2y + 2 = 0. Then the length of the chord, of the circle C, whose mid-point is (1, 2), is:
- 4 2
- 2 2
- 2 3
- 3
Answer
(3) 2 3
Solution
Centre lies on x=2 (bisector of (4,2),(0,2)) and on 3x+2y+2=0 ⇒ C(2,-4)
[figure]
r2=(4-2)2+(2+4)2=40
CM2=(1-2)2+(2+4)2=37
Half-chord = r2-CM2= 3
∴ chord =2 3
Answer: (3)