Sn=na 1+n(n- 1)d/2

Ss:St=as^2:at^2

(sa 1+s(s- 1)d):(ta 1+t(t- 1)d)=(a 1+(s^2- 1)d):(a 1+(t^2- 1)d)

(s+s(s- 1)(d/a 1)):(t+t(t- 1)(d/a 1))=( 1+(s^2- 1)(d/a 1)):( 1+(t^2- 1)(d/a 1))

D/a 1= 1 You can bring S T as any value at will.

a8:a23=8:23