АО=ОВ=R
∠AOB=60 градусов ⇒∠OАB=∠OBФ=(180°-60°)/2=60 градусов
S(cегмента)=(1/6)S(круга)- S(Δ AOB)=
=(1/6)*π*R^2-(1/2)*AO*BO*sin60 градусов=
=(1/6)*π*10^2-(1/2)*10*10*sqrt(3)/2=
=100*((π/6)-sqrt(3)/4)=
≈100*(0,5236-0,4330)=9,06
2)СН=ОС-ОН=10-(10*sin60 градусов)=10(1-(sqrt(3))/2)=
=10-5sqrt(3)
а=10
S=(2/3)*10*(10-5sqrt(3))+(10-5sqrt(3))^2/20=
=(200/3)-(100/3)sqrt(3)+(100-100sqrt(3)+75)/20=
=(200/3)-(100/3)sqrt(3)+(175/20)-5sqrt(3)=
=(4525/60)-(115/3)sqrt(3)≈75,41667-66,39528=9,02