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Explanation

Let `O` be the centre and `M` be mid-point of `AB`.

Then, `OMbotABimpliesM(1,4)`
Since, slope of `AB=0`
Equation of straight line `MO` is `x=1` and equation of diameter is `4y=x+7`.
`implies` Centre is `(1,2)`. Also, `O` is mid-point of `BD`
`implies((alpha+5)/(2),(beta+4)/(2))=(1,2)impliesalpha=-3`, `beta=0`
`:. AD=sqrt((-3+3)^(2)+(4-0)^(2))=4`
and `AB=sqrt(64+0)=8`
Thus, area of rectangle `=8xx4=32` sq units