# Find the Sum of G.P.: 1 + 3 + 9 + 27 + ………. to 12 Terms - Mathematics

Sum

Find the sum of G.P.:

1 + 3 + 9 + 27 + ………. to 12 terms

#### Solution

Given G.P. : 1 + 3 + 9 + 27+.......
Here,

first term, a = 1

common ratio, r =3/1 = 3 (r > 1)

number of terms to be added, n = 12

∴ Sn = (a(r^n-1))/(r-1)

"S"_12=(1(3^12-1))/(3-1)=(3^12-1)/2=(531441-1)/2=531440/2=265720

Concept: Simple Applications - Geometric Progression
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#### APPEARS IN

Selina Concise Maths Class 10 ICSE
Chapter 11 Geometric Progression
Exercise 11 (D) | Q 1.1 | Page 161