Jawabanmu

2014-05-21T15:17:12+07:00
Resonansi pertama :: n =  \frac{1}{4} λ
80 =  \frac{1}{4} λ
λ = 320 cm

resonansi kedua n =  \frac{3}{4} λ
n =  \frac{3}{4} x 320
n = 240 cm