Jawabanmu

2014-06-01T17:20:12+07:00
Dicari sisi alasnya dulu
s = √(200:8)
    = √25
    = 5 cm

p = 5, l=5, t=8
luas permukaan balok
= 2 (pl +pt+ lt)
= 2 ((5x5)+(5x8)+ (5x8))
= 2 (25+40+40)
= 2 (105)
= 210 cm2