Question

Suatu tangki berbentuk tabung tertutup dengan luas permukaan 79.200 cm dan jari-jari alas 70 cm berapakah liter isi tangki tersebut???

Answer 1

Verified answer

Tabung

Luas permukaan = 79200 cm²
2πr² + 2πr t = 79200
2πr (r + t) = 79200
2 . 22/7 . 70 (70 + t) = 79200
440 (70 + t) = 79200
70 + t = 79200/440
70 + t = 180
t = 180 - 70
t = 110 cm

Volume tabung
= πr² × t
= 22/7 . 70² . 110
= 1694000 cm³
= 1694 dm³
= 1694 liter

Answer 2

Verified answer

Lp = 2πr (t + r)
79200 = 2 (22/7) (70) (t + 70)
79200 = 440 (t + 70)
79200 = 440t + 30800
440t = 79200 - 30800
440t = 48400
t = 48400/440
t = 110 cm

Isi tangki / volume tangki
V = πr²t
V = 22/7 x 70 cm x 70 cm x 110 cm
V = 1694000 cm³
V = 1694 dm³
V = 1694 Liter