Q.

Let the line x + y = 1 meet the circle x2+y2=4 at the points A and B. If the line perpendicular to AB and passing through the mid point of the chord AB intersects the circle at C and D, then the area of the quadrilateral ADBC is equal to:          [2025]

1 37  
2 14  
3 214  
4 57  

Ans.

(3)

For points of intersection A and B.

Solving x + y = 1 and x2+y2=4, we get

A(172,1+72), B(1+72,172)

Slope of AB = –1

Slope of r bisector of AB = 1

For points of intersection C and D

Solving, x = y and x2+y2=4, we get

C(2,2) and D(2,2)

   Area of quadrilateral ADBC = 2 × Area of BCD

=2×12|2211+721721221|=214 sq. units.