Diketahui luas selimut tabung 1.408 cm,jika tinggi tabung 28cm,,maka diameter alasnya adalah....

Ls = 2fi x r x t
1408 = 2 x 22/7 x r x 28
1408 = 176 x r
r = 1408 / 176 = 8
D = 2r = 2 x 8
= 16

Dik. Luas selimut tabung = 1408 cm & Tinggi = 28cm
Dit. Diameter tabung ?

Jawab....

Luas selimut tabung (Lst) = 2 x π x r x t
@ Lst =  2 x π x r x t
@ 1408 = 2 x 22/7 x r x 28
@ 1408 x 7/22 = 56 x r
@ 448 = 56 x r
@ r = 448/56
@ r = 8cm ⇔ d = 2r = 2(8) = 16cm

Semoga membantu... ^_^