(S1+S2+S3+S4+S5+S6+S7+S8):8=38
afli suma celor opt suprafete S1+S2+S3+S4+S5+S6+S7+S8=304
aplici faptul ca media aritmetica a primelor patru suprafete este 29 : S1+S2+S3+S4=29*4=156
S5+S6+S7+S8+156=304
S5+S6+S7+S8=304-156
afli suma utimelor partu suprafete S5+S6+S7+S8=148
calculezi media aritmetica(S5+S6+S7+S8):4=148:4=37