Find the equation of the circle which circumscribes the triangle formed by the lines:
2x + y - 3 = 0, x + y - 1 = 0 and 3x + 2y - 5 = 0
Given that we need to find the equation of the circle formed by the lines:
⇒ 2x + y - 3 = 0
⇒ x + y - 1 = 0
⇒ 3x + 2y - 5 = 0
On solving these lines we get the intersection points A(2, - 1), B(3, - 2), C(1,1)
We know that the standard form of the equation of a circle is given by:
⇒ x2 + y2 + 2ax + 2by + c = 0 .....(1)
Substituting (2, - 1) in (1), we get
⇒ 22 + (- 1)2 + 2a(2) + 2b(- 1) + c = 0
⇒ 4 + 1 + 4a - 2b + c = 0
⇒ 4a - 2b + c + 5 = 0 ..... (2)
Substituting (3, - 2) in (1), we get
⇒ 32 + (- 2)2 + 2a(3) + 2b(- 2) + c = 0
⇒ 9 + 4 + 6a - 4b + c = 0
⇒ 6a - 4b + c + 13 = 0 ..... (3)
Substituting (1,1) in (1), we get
⇒ 12 + 12 + 2a(1) + 2b(1) + c = 0
⇒ 1 + 1 + 2a + 2b + c = 0
⇒ 2a + 2b + c + 2 = 0 ..... (4)
Solving (2), (3), (4) we get
⇒ .
Substituting these values in (1), we get
⇒
⇒ x2 + y2 - 13x - 5y + 16 = 0
∴ The equation of the circle is x2 + y2 - 13x - 5y + 16 = 0.