notam coarda AB si centrul cercului O
deoarece m(∡AOB)=60° ⇒triunghiul AOB echilateral
A(AOB)=L²√3/4=36²√3/4=324√3 ≈561,184 mm²
Asect=(π×r²×n)/360°=(π×36²×60°)/360°=216π ≈678,24 mm²
aria suprafete cerute=216π-324√3=678,24-561,184=117,0555 ≈117,06 mm²
sau cu formula
Asegment circular=r²×(π×n°/360°-sin n/2×cos n/2)=36²×[π×60°/360°-sin 60°/2 ×cos 60°/2]=1296×(3,14/6-sin 30°×cos 30°)=1296×(3,14/6-1/2×√3/2)= =1296×[0,52(3)-0,4330127]=1296×0,9032063=117,0555≈117,06 mm²
