L=10m si l=r=1m.___________________
__a.)A1=L•l=10•1=10m²______________
__b.)A2=Aria unei jumatati de cerc + aria altei jumatati de cerc=A unui cerc intreg=pi •r²=pi•1²=pi.___________________c.)Lsemi cerc+L semicerc=Lcerc=2•r•pi=2•1•pi=2•pi=2•3,14=6,28