Let us assume that the common difference of the A.P. is 'd'. Then, we can say that a=b−d,c=b+d It is given that a+b+c=
3
2
. i.e. b = 1/2. It is given that a2,b2 and c2 are in Geometric Progression. Hence, we can say that b4=a2∗c2 b4=(b2−d2)2 ⇒(b2+d2−b2)(b2−d2+b2)=0 Therefore,(b2−d2+b2)=0 i.e. d=