Jawabanmu

2014-05-01T00:10:13+07:00
Dik: D=20 cm
       pi=3,14 cm
       t=25 cm
dit:luas permukaan tabung=...??
   penyel:
 L =  2 x pi x r(r+t)
    = 2 x 3,14 x 10(10+25)
    = 6,28 x 10(35)
    = 62,8(35)
    = 2198
b.2198
1 5 1
2014-05-01T00:10:52+07:00
Rumus luas perm.tabung:
2. \pi .r(r+t)
=2 . 3,14 . 20cm/2 (20cm/2+25cm)
=2 . 3,14.10cm (10cm+25cm)
=62,8cm (35cm)
=2198 cm^2