length of diag=√2lenght of square.
so,S1=10,S2=5√2
............................Sn=10/2^{n-1/2}
area of Sn=100/2^{n-1/}
so ans is ,b,c,d
length of diag=√2lenght of square.
so,S1=10,S2=5√2
............................Sn=10/2^{n-1/2}
area of Sn=100/2^{n-1/}
so ans is ,b,c,d