Tabung luas permukaannya
sama dengan volumenya.
Rumus mencari r dan t
berturut-turut, adalah:
(a.) r = 2t÷(2-t), t = 2r÷(2-r)
(b.) r = 2t÷(t-2), t = 2r÷(r-2)
(c.) r = 2t÷(t+2), t = 2r÷(r+2)
(d.) r = 2t÷(t-2), t = 2r÷(2-r)
(e.) r = 2t÷(2-t), t = 2r÷(r-2)
Quiz (+50):
bangun ruang
tabung
volume = luas permukaan
πr²t = πr(2r + 2t)
rt = 2r + 2t
r(t – 2) = 2t
r = 2t/(t – 2)
rt = 2r + 2t
t(r – 2) = 2r
t = 2r/(r – 2)
opsi : B
Penyelesaian:
V=Lp
Πr²t=2Πr(r+t)
rt=2(r+t)
rt=2r+2t
rt-2r=2t
r(t-2)=2t
r=2t/t-2
—————————————-
V=Lp
Πr²t=2Πr(r+t)
rt=2(r+t)
rt=2r+2t
rt-2t=2r
t(r-2)=2r
t=2r/(r-2)
—————————————-
Maka rumus yang benar adalah B.