Question

1. Volume sebuah tabung 385 cm2. Jika diameter alasnya 7cm. Luas selimut tabung adalah....
A. 220 cm2
B. 297 cm2
C. 440 cm2
D. 517 cm2

Answer 1

Dik = Volume = 385 cm²
Diameter = 7 cm
r = 3,5 cm

Dit = Luas selimut ?
Jawab =
Cari dulu tingginya
Volume = pi * r² * t
385 = 22/7 * 3,5 * 3,5 * t
t = 385 * 7 / (22*3,5*3,5)
t = 385 * 2 / (22 * 3,5)
t = 770 / 77
t = 10 cm

Luas selimut = 2 * pi * r * t
= 2 * 22/7 * 3,5 * 10
= 2* 11 * 10
= 220 cm² A