Mohon bantuannya soal mtk​

Deret Geometri Tak Hingga

S∞ = a/(1 – r)

28 1/2 = 19/(1 – r)

57/2 = 19/(1 – r)

kedua ruas bagi 19

3/2 = 1/(1 – r)

1 – r = 2/3

r = 1 – 2/3

r = 1/3