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Here, C (0,0)point is considered as original point of X-Y axises.

 

BD=a/2;

BC=a;

CD²= BC² – BD²

=>CD=(√3/2)a

Now OB=OA=(√3/2)a -a/2=(√3/2 – 1/2)a =ka

Area of the white region = π*a*a/4

Area of white region = a*a –  π*a*a/4

Area of white region = π*a*a/4 – a*a –  π*a*a/4

Area of dotted region =(Area of white region – Area of striped region)*2

Area of rest region = a² – Area of dotted region  – Area of striped region

 

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