Jumlah deret geometri 18 + 6 + 2 + 2/3 + ... adl pake cara please

a = U1 = 18

r = U2/U1
r = 6/18
r = 1/3

Jumlah deret geometri
S~ = a / (1 - r)
S~ = 18 / (1 - 1/3)
S~ = 18 / (3/3 - 1/3)
S~ = 18 / (2/3)
S~ = 18/1 x 3/2
S~ = 9 x 3
S~ = 27

Jadi jumlah deret geometri tak hingga dari data tsb adl 27