Question

Puteți face la fiecare doar punctul a.
Mulțumesc.

Answer 1

39a)
A=280 cm²  
A=2L×l+2L×h+2l×h=2L×(l+h)+2(l×h)=2×10×11+2(l×h)=220+2(l×h)
220+2(l×h)=280
l×h=(280-220)/2=30   
V=L×l×h=10×30=300 cm²

40a)
L+l=35
L+h=25
l+h=18
L+l+L+h+l+h=35+25+18
2(L+l+h)=78
L+l+h=39   ⇒ h=39-35=4 
                      l=39-25=14
                      L=39-18=21
At=2×(21×14+21×4+14×4)=2×(294+84+56)=2×434=868  cm²


41a)
190 hm=1900 dam
7700 dm=77 dam
A=1900×77=146300 dam²

42a)
1700 mm = 1,7 m
310 hm=31000 m
P=2×(1,7+31000)=2×31001,7=62003,4 m