Question

If equation of circle which touches the line $\frac { x } { 3 }$ + = 1 and both coordinates axis and lies below the line and whose centre lies in I^stquadrant is x² + y² – 2cx – 2cy + c² = 0 then value of c =

• A. 1
• B. 2
• C. 3
• D. 6

Answer 1

Answer: (A)

1

Answer 2

line 4x + 3y = 12

centre (c, c), r = c

p = r

$\frac { | 4 c + 3 c - 12 | } { 5 }$ = c

|7c – 12| = 5c

ή 7c – 12 = ± 5c

ή 12c = 12 or 2c = 12

ή c = 1 or c = 6

Q circle lies below line

ή centre (1, 1) c = 1