Q23 of 63 Page 202

If the lines 2x – 3y = 5 and 3x – 4y = 7 are the diameters of a circle of area 154square units, then obtain the equation of the circle.

Since, diameters of a circle intersect at the centre of a circle,


2x – 3y = 5 -------- (i)


3x – 4y = 7 -------- (ii)


Solving the above mentioned equations,


6x – 9y = 15 [Multiplying equation (i) by 3}


6x – 8y = 14 [Multiplying equation (ii) by 2}


y = 1


y = -1


Putting y = -1, in equation (i)


2x – 3(-1) = 5


2x + 3 = 5


2x = 2


x = 1


Coordinates of centre = (1,-1)


Area = (Given)




r = 7 units


Since, the equation of a circle having centre (h,k), having radius as "r" units, is


(x – h)2 + (y – k)2 = r2


(x – 1)2 + (y – (-1))2 = 72


x2 - 2x +1 + (y + 1)2 = 49


x2 - 2x + 1 + y2 + 2y + 1 – 49 = 0


x2 - 2x + y2 + 2y – 47 = 0


Hence the required equation of the given circle is x2 - 2x + y2 + 2y – 47 = 0.


More from this chapter

All 63 →