d=a√2
Obw=4a
Pole=a^2
a) 7 √2 = a √2 //: √2
7=a
Obw=4*7=28cm
Pole=7^2=49cm^2
b) 4=a √2 //: √2
4/√2 = a
4 * √2 / √2 * √2 = a
4√2 /2 = a
2 √2 =a
Obw=4*2√2 = 8√2dm
Pole= (2√2dm)^2 = 8dm^2
c) 12 = a √2 //: √2
12/ √2 = a
12* √2 / √2* √2 = a
6 √2 = a
Obw= 4*6 √2= 24√2m
Pole= (6 √2m)^2 =72m^2