Q.

Let ABCD and AEFG be squares of sides 4 and 2 units respectively. the point E is on the line segment AB and the point F is on the diagonal AC. Then the radius r of the circle passing through the point F and touching the line segments BC and CD satisfies :          [2024]

1 2r24r+1=0  
2 r28r+8=0  
3 r = 1  
4 2r28r+7=0  

Ans.

(2)

Let r be the radius of circle and centre at C(r, r).

Then, FC2 = r2

   (r 2)2 + (r  2)2 = r2 

   r2  8r + 8 = 0.