Find the indicated sum for each geometric series.
1) S7 for 972 + 324 ?108.....
Dividing successive terms yields a common ratio of r = 1/3.
With a = the first term, n = the number of terms and S = the sum of n terms,
S = a(r^n - 1)/(r - 1) = 972[(1/3)^7 - 1]/(1/3 - 1) = 1457.333...
