The centre of circle inscribed in square formed by the lines and , is
- A.(4, 7)
- B.(7, 4)
- C.(9, 4)
- D.(4, 9)
Show answer and solution
Correct option: A
Solution
The lines x²-8x+12=0 factor as (x-2)(x-6)=0, giving x=2 and x=6. The lines y²-14y+45=0 factor as (y-5)(y-9)=0, giving y=5 and y=9. These four lines form a square, and the inscribed circle's centre is simply the midpoint of the square: x = (2+6)/2 = 4, y = (5+9)/2 = 7, giving centre (4, 7).
[AIEEE 2003]