# Please give detailed explanation. Choose correct option.

Solution:

Let , CD  =  a  and given AB  =  2 CD , So

AB  =  2 a

And

Radius of given circle  =  r  , then AD  =  2r ( As AD is perpendicular to AB and CD )

Now we form our diagram , As :

Here , A be at origin and AB and AD at x - axis and y - axis respectively .

So,

Coordinates of A ( 0 , 0 ) , B ( 2a  , 0 ) , C ( a  , 2r )  and D ( 2r , 0 )

We can see ABCD is a trapezium , and we know area of trapezium  =

So,

Area of ABCD  =

Now we draw a right angle triangle OBC and a perpendicular line from center to BC , As :

So,

But radius can't be negative , So we get